一、前言

HTTP/2 作為 HTTP/1.1 的繼任者，在效能、效率以及用戶體驗方面帶來了顯著的提升。它引入了多路複用、頭部壓縮、伺服器推送等關鍵特性，大幅減少了網頁載入時間並優化了資源利用率。HTTP/2 並不僅限於傳輸文本數據，它也能高效地傳輸二進制資料，例如圖像、音頻和影片等。然而，Java 在對 HTTP/2 的支援上並非一蹴而就，而是在不同版本中逐步完善。 值得注意的是，Java 原生 API (例如 java.net.http 包) 主要提供了 HTTP/2 客戶端 (Client) 的支援，並沒有提供直接構建 HTTP/2 伺服器 (Server) 的方式。 因此，在 Java 中建立 HTTP/2 伺服器通常需要依賴第三方函式庫，例如 Netty。本文將深入探討 Java 7 至 17 各版本在 HTTP/2 方面的發展，分析其關鍵特性、架構、相關工具以及具體範例，幫助讀者理解 Java 如何逐步擁抱並應用 HTTP/2，以及如何透過第三方函式庫建立 HTTP/2 伺服器。

一、前言
- 目錄
二、Java 7/8：HTTP/2 的萌芽
三、Java 9：HTTP/2 客戶端 API 的曙光
四、Java 11：HTTP Client API 的正式加入
五、HTTP Server 和 HTTP/2 Client 範例
六、使用第三方套件建立 HTTP/2 伺服器
七、Java 12 ~ 17：持續的改進與優化
八、總結
附錄

二、Java 7/8：HTTP/2 的萌芽

返回目錄

在 Java 7 和 8 中，官方標準庫並未直接提供 HTTP/2 的原生支援。當時，如果開發者需要使用 HTTP/2，通常需要依賴第三方函式庫，例如：

Netty： 一個高度可擴展的非同步事件驅動網路應用框架，提供了強大的 HTTP/2 支援。
Jetty： 一個輕量級的 Java HTTP 伺服器和 Servlet 容器，通過其 HTTP/2 模組可以支援 HTTP/2。

這時期使用 HTTP/2 往往需要額外的依賴和配置，使得應用程式的部署和維護成本較高。儘管如此，這也為後續 Java 版本原生支援 HTTP/2 打下了基礎。

架構圖(基於第三方函式庫):

範例 (使用 Netty - 簡化):

(範例僅供示意，實際程式碼較為複雜，需參考 Netty 文件)

// 使用Netty設定HTTP/2客戶端
// ... 省略部分程式碼 ...
public class Http2Client {
    public static void main(String[] args) throws Exception {
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group)
             .channel(NioSocketChannel.class)
             .handler(new Http2ClientInitializer()); // 初始化HTTP/2處理器
            Channel ch = b.connect("example.com", 443).sync().channel();
            // 發送HTTP/2請求
            // ...
            ch.closeFuture().sync();
        } finally {
            group.shutdownGracefully();
        }
    }
}
​x
 
// 使用Netty設定HTTP/2客戶端
// ... 省略部分程式碼 ...
public class Http2Client {
    public static void main(String[] args) throws Exception {
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group)
             .channel(NioSocketChannel.class)
             .handler(new Http2ClientInitializer()); // 初始化HTTP/2處理器
            Channel ch = b.connect("example.com", 443).sync().channel();
            // 發送HTTP/2請求
            // ...
            ch.closeFuture().sync();
        } finally {
            group.shutdownGracefully();
        }
    }
}
​

三、Java 9：HTTP/2 客戶端 API 的曙光

返回目錄

Java 9 引入了新的 HTTP Client API ，這是一個重要的里程碑。這個 API 提供了一個現代化且更為易用的 HTTP 客戶端，同時，它也提供了 HTTP/2 的初步支援。雖然 Java 9 的 HTTP Client API 仍處於孵化階段 (Incubator Module)，但它展現了 Java 對 HTTP/2 的積極擁抱。

架構圖(Java 9 HTTP Client API):

工具:

java.net.http 相關的類別，例如 HttpClient , HttpRequest , HttpResponse 。

範例 (Java 9 HTTP Client API - 簡化):

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class Http2Client {
    public static void main(String[] args) throws Exception {
        HttpClient client = HttpClient.newBuilder()
                .version(HttpClient.Version.HTTP_2)
                .build();

        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://example.com/"))
                .build();

        HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
        System.out.println(response.body());
    }
}
xxxxxxxxxx
 
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
​
public class Http2Client {
    public static void main(String[] args) throws Exception {
        HttpClient client = HttpClient.newBuilder()
                .version(HttpClient.Version.HTTP_2)
                .build();
​
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://example.com/"))
                .build();
​
        HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
        System.out.println(response.body());
    }
}
​

注意: Java 9的HTTP Client API在最初是incubator module, 後續版本才正式成為標准API

四、Java 11：HTTP Client API 的正式加入

返回目錄

Java 11 正式移除了 Incubator Module，將 Java 9 引入的 HTTP Client API 納入標準 API。這意味著開發者可以無需擔心 API 的變動，直接使用 java.net.http 包下的類別進行 HTTP/2 通訊。這大大簡化了開發流程，降低了程式碼的複雜度。Java 11 的 HTTP Client API 支援同步與非同步請求，提供了完善的錯誤處理機制，並可配合 TLS (Transport Layer Security) 使用，安全高效。

架構圖(Java 11 HTTP Client API):

工具:

java.net.http 包中的 HttpClient , HttpRequest , HttpResponse , WebSocket 等類別。

範例 (Java 11 HTTP Client API - 同步請求): (與 Java 9 範例類似，但使用正式 API)

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class Http2Client {
    public static void main(String[] args) throws Exception {
        HttpClient client = HttpClient.newBuilder()
                .version(HttpClient.Version.HTTP_2)
                .build();

        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://www.google.com/")) // 使用 HTTPS 和 Google 首頁
                .build();

        HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
        System.out.println("Response Status Code: " + response.statusCode());
        // System.out.println(response.body()); // 如果不需要印出全部內容，可以將這行註解
        System.out.println("Response Headers: " + response.headers());
    }
}
xxxxxxxxxx
 
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
​
public class Http2Client {
    public static void main(String[] args) throws Exception {
        HttpClient client = HttpClient.newBuilder()
                .version(HttpClient.Version.HTTP_2)
                .build();
​
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://www.google.com/")) // 使用 HTTPS 和 Google 首頁
                .build();
​
        HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
        System.out.println("Response Status Code: " + response.statusCode());
        // System.out.println(response.body()); // 如果不需要印出全部內容，可以將這行註解
        System.out.println("Response Headers: " + response.headers());
    }
}
​

範例 (Java 11 HTTP Client API - 非同步請求):

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.util.concurrent.CompletableFuture;

public class Http2ClientAsync {
    public static void main(String[] args) throws Exception {
        HttpClient client = HttpClient.newBuilder()
                .version(HttpClient.Version.HTTP_2)
                .build();

        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://www.google.com/")) // 使用 HTTPS 和 Google 首頁
                .build();

        CompletableFuture<HttpResponse<String>> responseFuture = client.sendAsync(request, HttpResponse.BodyHandlers.ofString());

        responseFuture.thenAccept(response -> {
                  System.out.println("Response Status Code: " + response.statusCode());
                  // System.out.println(response.body()); // 如果不需要印出全部內容，可以將這行註解
                  System.out.println("Response Headers: " + response.headers());
              }).join(); // 等待非同步操作完成
    }
}
xxxxxxxxxx
 
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.util.concurrent.CompletableFuture;
​
public class Http2ClientAsync {
    public static void main(String[] args) throws Exception {
        HttpClient client = HttpClient.newBuilder()
                .version(HttpClient.Version.HTTP_2)
                .build();
​
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://www.google.com/")) // 使用 HTTPS 和 Google 首頁
                .build();
​
        CompletableFuture<HttpResponse<String>> responseFuture = client.sendAsync(request, HttpResponse.BodyHandlers.ofString());
​
        responseFuture.thenAccept(response -> {
                  System.out.println("Response Status Code: " + response.statusCode());
                  // System.out.println(response.body()); // 如果不需要印出全部內容，可以將這行註解
                  System.out.println("Response Headers: " + response.headers());
              }).join(); // 等待非同步操作完成
    }
}
​

五、HTTP Server 和 HTTP/2 Client 範例

返回目錄

本節使用 Java 內建的 com.sun.net.httpserver.HttpsServer 來建立一個簡單的 HTTPS 伺服器，並使用 java.net.http.HttpClient 建立 HTTP/2 客戶端。這裡需要 JDK 11 以上的版本才能執行。

資料夾目錄：

.
├── lib
│   ├── bcpkix-jdk18on-1.79.jar
│   ├── bcprov-jdk18on-1.79.jar
│   └── bcutil-jdk18on-1.79.jar
└── src
    ├── SelfSignedCertificateGenerator.class
    ├── SelfSignedCertificateGenerator.java
    ├── SimpleHttp2Client.java
    └── SimpleHttpServer.java

xxxxxxxxxx
 
.
├── lib
│   ├── bcpkix-jdk18on-1.79.jar
│   ├── bcprov-jdk18on-1.79.jar
│   └── bcutil-jdk18on-1.79.jar
└── src
    ├── SelfSignedCertificateGenerator.class
    ├── SelfSignedCertificateGenerator.java
    ├── SimpleHttp2Client.java
    └── SimpleHttpServer.java
​

說明：

HTTPS (Hypertext Transfer Protocol Secure): HTTPS 是 HTTP 的安全版本，它通過 TLS/SSL 協定加密客戶端和伺服器之間的通訊，保障資料傳輸的安全性。為了建立 HTTPS 連線，伺服器需要一個憑證。
自簽憑證： 為了簡化開發流程，範例使用了自簽憑證。自簽憑證是由伺服器自己生成的憑證，而不是由受信任的憑證頒發機構 (CA) 簽發。在生產環境中，應該使用 CA 簽發的憑證。
com.sun.net.httpserver ： 這是 Java SE 提供的一個輕量級 HTTP 伺服器 API。它可以用於快速建立簡單的 HTTP 伺服器，但功能相對有限，不適用於大型或高負載的應用程式。
java.net.http.HttpClient ： 這是 Java 9 中引入的標準 HTTP 客戶端 API。它支援 HTTP/1.1 和 HTTP/2，提供了同步和非同步請求等功能。
HTTP/2： HTTP/2 是 HTTP/1.1 的改進版本，具有多路複用、頭部壓縮等特性，可以提高網頁載入速度和效能。

程式碼結構： 這個範例程式碼被拆分為幾個檔案

(5.1) 使用 Bouncy Castle 建立自簽憑證

SelfSignedCertificateGenerator.java ：

功能： 使用 Bouncy Castle 函式庫生成自簽憑證和相關的金鑰儲存 (KeyStore) 檔案。
說明：
- generateRSAKeyPair(int keySize) : 生成 RSA 金鑰對。
- createCertificate(KeyPair keyPair, String dnString, int validityDays) : 使用金鑰對，產生自簽憑證。
- saveCert(String aliasName, X509Certificate cert, PrivateKey key, char[] keyStorePassword) : 將憑證與私鑰儲存到金鑰儲存檔案中。
Bouncy Castle: 這是一個第三方加密庫，用於生成自簽憑證證書。

下載 Bouncy Castle 第三方套件： Bouncy Castle 官方網站

import org.bouncycastle.asn1.x500.X500Name;
import org.bouncycastle.asn1.x500.X500NameBuilder;
import org.bouncycastle.asn1.x500.style.BCStyle;
import org.bouncycastle.asn1.x509.BasicConstraints;
import org.bouncycastle.cert.X509CertificateHolder;
import org.bouncycastle.cert.X509v3CertificateBuilder;
import org.bouncycastle.cert.jcajce.JcaX509CertificateConverter;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.operator.ContentSigner;
import org.bouncycastle.operator.jcajce.JcaContentSignerBuilder;

import java.io.File;
import java.io.FileOutputStream;
import java.math.BigInteger;
import java.security.*;
import java.security.cert.X509Certificate;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.util.Date;
import java.util.Random;

public class SelfSignedCertificateGenerator {

    private static final String CERTIFICATE_ALIAS = "my-self-signed-cert";
    private static final String CERTIFICATE_ALGORITHM = "RSA";
    private static final String CERTIFICATE_DN = "CN=my-test-cn, O=my-test-org, L=my-test-loc, ST=my-test-st, C=tw";
    private static final String CERTIFICATE_NAME = "keystore.jks";
    private static final int CERTIFICATE_BITS = 2048;
    private static final int CERTIFICATE_DAYS = 365 * 10;

    static {
        Security.addProvider(new BouncyCastleProvider());
    }

    public static void main(String[] args) {
        try {
            KeyPair keyPair = generateRSAKeyPair(CERTIFICATE_BITS);
            X509Certificate cert = SelfSignedCertificateGenerator.createCertificate(
                    keyPair, CERTIFICATE_DN, CERTIFICATE_DAYS);
            System.out.println("自簽憑證建立成功!");
            System.out.println("憑證主題: " + cert.getSubjectX500Principal().getName());
            System.out.println(cert);
        } catch (Exception e) {
            System.err.println("產生自簽憑證時發生錯誤: " + e.getMessage());
            e.printStackTrace();
        }
    }

    public static X509Certificate createCertificate(KeyPair keyPair, String dnString, int validityDays)
            throws Exception {
        X500Name issuer = buildX500Name(dnString);
        X500Name subject = issuer;
        X509Certificate certificate = generateSelfSignedCertificate(keyPair, issuer, subject, validityDays);
        return certificate;
    }

    public static KeyPair generateRSAKeyPair(int keySize) throws NoSuchAlgorithmException, NoSuchProviderException {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(CERTIFICATE_ALGORITHM, "BC");
        keyPairGenerator.initialize(keySize, new SecureRandom());
        return keyPairGenerator.generateKeyPair();
    }

    private static X500Name buildX500Name(String dnString) {
        X500NameBuilder builder = new X500NameBuilder(BCStyle.INSTANCE);
        if (dnString != null && !dnString.isBlank()) {
            String[] parts = dnString.split(",");
            for (String part : parts) {
                String[] keyValue = part.trim().split("=", 2);
                if (keyValue.length == 2) {
                    String attrName = keyValue[0].trim();
                    String attrValue = keyValue[1].trim();
                    builder.addRDN(BCStyle.INSTANCE.attrNameToOID(attrName), attrValue);
                }
            }
        }
        return builder.build();
    }

    private static X509Certificate generateSelfSignedCertificate(KeyPair keyPair, X500Name issuer, X500Name subject,
            int days)
            throws Exception {
        LocalDateTime now = LocalDateTime.now();
        Date notBefore = Date.from(now.toInstant(ZoneOffset.UTC));
        Date notAfter = Date.from(now.plusDays(days).toInstant(ZoneOffset.UTC));

        BigInteger serialNumber = new BigInteger(128, new Random());

        // 將 BCRSAPublicKey 轉換為 SubjectPublicKeyInfo
        org.bouncycastle.asn1.x509.SubjectPublicKeyInfo subjectPublicKeyInfo = org.bouncycastle.asn1.x509.SubjectPublicKeyInfo
                .getInstance(keyPair.getPublic().getEncoded());

        // 建立 X509v3 Certificate Builder
        X509v3CertificateBuilder certificateBuilder = new X509v3CertificateBuilder(
                issuer, serialNumber, notBefore, notAfter, subject, subjectPublicKeyInfo);

        // 設定基本限制
        BasicConstraints basicConstraints = new BasicConstraints(true); // true 表示是 CA
        certificateBuilder.addExtension(org.bouncycastle.asn1.x509.Extension.basicConstraints, true, basicConstraints);

        // 使用私鑰簽署憑證
        ContentSigner contentSigner = new JcaContentSignerBuilder("SHA256withRSA").setProvider("BC")
                .build(keyPair.getPrivate());
        X509CertificateHolder holder = certificateBuilder.build(contentSigner);

        // 將憑證轉換為 X509Certificate 物件
        JcaX509CertificateConverter converter = new JcaX509CertificateConverter().setProvider("BC");
        return converter.getCertificate(holder);
    }

    public static void saveCert(String aliasName, X509Certificate cert, PrivateKey key, char[] keyStorePassword)
            throws Exception {
        KeyStore keyStore = KeyStore.getInstance("JKS");
        keyStore.load(null, null);
        String alias = aliasName.isBlank() ? CERTIFICATE_ALIAS : aliasName;
        keyStore.setKeyEntry(alias, key, keyStorePassword,
                new java.security.cert.Certificate[] { cert });
        File file = new File(".", CERTIFICATE_NAME);
        keyStore.store(new FileOutputStream(file), keyStorePassword);
    }
}
xxxxxxxxxx
 
import org.bouncycastle.asn1.x500.X500Name;
import org.bouncycastle.asn1.x500.X500NameBuilder;
import org.bouncycastle.asn1.x500.style.BCStyle;
import org.bouncycastle.asn1.x509.BasicConstraints;
import org.bouncycastle.cert.X509CertificateHolder;
import org.bouncycastle.cert.X509v3CertificateBuilder;
import org.bouncycastle.cert.jcajce.JcaX509CertificateConverter;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.operator.ContentSigner;
import org.bouncycastle.operator.jcajce.JcaContentSignerBuilder;
​
import java.io.File;
import java.io.FileOutputStream;
import java.math.BigInteger;
import java.security.*;
import java.security.cert.X509Certificate;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.util.Date;
import java.util.Random;
​
public class SelfSignedCertificateGenerator {
​
    private static final String CERTIFICATE_ALIAS = "my-self-signed-cert";
    private static final String CERTIFICATE_ALGORITHM = "RSA";
    private static final String CERTIFICATE_DN = "CN=my-test-cn, O=my-test-org, L=my-test-loc, ST=my-test-st, C=tw";
    private static final String CERTIFICATE_NAME = "keystore.jks";
    private static final int CERTIFICATE_BITS = 2048;
    private static final int CERTIFICATE_DAYS = 365 * 10;
​
    static {
        Security.addProvider(new BouncyCastleProvider());
    }
​
    public static void main(String[] args) {
        try {
            KeyPair keyPair = generateRSAKeyPair(CERTIFICATE_BITS);
            X509Certificate cert = SelfSignedCertificateGenerator.createCertificate(
                    keyPair, CERTIFICATE_DN, CERTIFICATE_DAYS);
            System.out.println("自簽憑證建立成功!");
            System.out.println("憑證主題: " + cert.getSubjectX500Principal().getName());
            System.out.println(cert);
        } catch (Exception e) {
            System.err.println("產生自簽憑證時發生錯誤: " + e.getMessage());
            e.printStackTrace();
        }
    }
​
    public static X509Certificate createCertificate(KeyPair keyPair, String dnString, int validityDays)
            throws Exception {
        X500Name issuer = buildX500Name(dnString);
        X500Name subject = issuer;
        X509Certificate certificate = generateSelfSignedCertificate(keyPair, issuer, subject, validityDays);
        return certificate;
    }
​
    public static KeyPair generateRSAKeyPair(int keySize) throws NoSuchAlgorithmException, NoSuchProviderException {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(CERTIFICATE_ALGORITHM, "BC");
        keyPairGenerator.initialize(keySize, new SecureRandom());
        return keyPairGenerator.generateKeyPair();
    }
​
    private static X500Name buildX500Name(String dnString) {
        X500NameBuilder builder = new X500NameBuilder(BCStyle.INSTANCE);
        if (dnString != null && !dnString.isBlank()) {
            String[] parts = dnString.split(",");
            for (String part : parts) {
                String[] keyValue = part.trim().split("=", 2);
                if (keyValue.length == 2) {
                    String attrName = keyValue[0].trim();
                    String attrValue = keyValue[1].trim();
                    builder.addRDN(BCStyle.INSTANCE.attrNameToOID(attrName), attrValue);
                }
            }
        }
        return builder.build();
    }
​
    private static X509Certificate generateSelfSignedCertificate(KeyPair keyPair, X500Name issuer, X500Name subject,
            int days)
            throws Exception {
        LocalDateTime now = LocalDateTime.now();
        Date notBefore = Date.from(now.toInstant(ZoneOffset.UTC));
        Date notAfter = Date.from(now.plusDays(days).toInstant(ZoneOffset.UTC));
​
        BigInteger serialNumber = new BigInteger(128, new Random());
​
        // 將 BCRSAPublicKey 轉換為 SubjectPublicKeyInfo
        org.bouncycastle.asn1.x509.SubjectPublicKeyInfo subjectPublicKeyInfo = org.bouncycastle.asn1.x509.SubjectPublicKeyInfo
                .getInstance(keyPair.getPublic().getEncoded());
​
        // 建立 X509v3 Certificate Builder
        X509v3CertificateBuilder certificateBuilder = new X509v3CertificateBuilder(
                issuer, serialNumber, notBefore, notAfter, subject, subjectPublicKeyInfo);
​
        // 設定基本限制
        BasicConstraints basicConstraints = new BasicConstraints(true); // true 表示是 CA
        certificateBuilder.addExtension(org.bouncycastle.asn1.x509.Extension.basicConstraints, true, basicConstraints);
​
        // 使用私鑰簽署憑證
        ContentSigner contentSigner = new JcaContentSignerBuilder("SHA256withRSA").setProvider("BC")
                .build(keyPair.getPrivate());
        X509CertificateHolder holder = certificateBuilder.build(contentSigner);
​
        // 將憑證轉換為 X509Certificate 物件
        JcaX509CertificateConverter converter = new JcaX509CertificateConverter().setProvider("BC");
        return converter.getCertificate(holder);
    }
​
    public static void saveCert(String aliasName, X509Certificate cert, PrivateKey key, char[] keyStorePassword)
            throws Exception {
        KeyStore keyStore = KeyStore.getInstance("JKS");
        keyStore.load(null, null);
        String alias = aliasName.isBlank() ? CERTIFICATE_ALIAS : aliasName;
        keyStore.setKeyEntry(alias, key, keyStorePassword,
                new java.security.cert.Certificate[] { cert });
        File file = new File(".", CERTIFICATE_NAME);
        keyStore.store(new FileOutputStream(file), keyStorePassword);
    }
}
​

(5.2) 使用原生 JAVA SE API 建立 Local Server

SimpleHttpServer.java ：

功能： 建立一個簡單的 HTTPS 伺服器，監聽 8443 端口。
說明：
- 首先，使用 SelfSignedCertificateGenerator 生成自簽憑證與金鑰，並載入到 KeyStore 中。
- 接著，使用 SSLContext 設定 TLS/SSL 連線所需的憑證和密碼。
- 使用 HttpsServer.create() 建立一個 HttpsServer 物件，並設定 HttpsConfigurator 來配置 SSL。
- 使用 createContext() 設定請求處理邏輯，這裡只簡單返回 Hello, HTTP from Simple Server. 的文字訊息。
- 伺服器處理請求時，會輸出 HTTP 版本和請求 Header。

import com.sun.net.httpserver.Filter;
import com.sun.net.httpserver.Headers;
import com.sun.net.httpserver.HttpContext;
import com.sun.net.httpserver.HttpsConfigurator;
import com.sun.net.httpserver.HttpsParameters;
import com.sun.net.httpserver.HttpsServer;
import javax.net.ssl.*;

import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.security.*;
import java.security.cert.X509Certificate;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Executors;

public class SimpleHttpServer {
    public static void main(String[] args) throws Exception {
        // 創建一個 KeyStore 來存放憑證
        KeyStore keyStore = KeyStore.getInstance("JKS");
        keyStore.load(null, null); // 載入空 KeyStore
        // 產生自簽名憑證，此處簡化，正式環境請使用正式憑證
        // KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
        // keyPairGenerator.initialize(2048); // 初始化 KeyPairGenerator
        // KeyPair keyPair = keyPairGenerator.generateKeyPair(); // 產生 KeyPair
        KeyPair keyPair = SelfSignedCertificateGenerator.generateRSAKeyPair(2048);
        X509Certificate selfSignedCert = SelfSignedCertificateGenerator.createCertificate(keyPair,
                "CN=localhost, O=my-test-org, L=my-test-loc, ST=my-test-st, C=tw", 365); // 生成自簽名憑證
        keyStore.setKeyEntry("mykey", keyPair.getPrivate(), "password".toCharArray(),
                new X509Certificate[] { selfSignedCert }); // 設定憑證

        // 建立 SSL Context
        SSLContext sslContext = SSLContext.getInstance("TLS");
        KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
        keyManagerFactory.init(keyStore, "password".toCharArray());
        TrustManagerFactory trustManagerFactory = TrustManagerFactory
                .getInstance(TrustManagerFactory.getDefaultAlgorithm());
        trustManagerFactory.init(keyStore);
        sslContext.init(keyManagerFactory.getKeyManagers(), trustManagerFactory.getTrustManagers(), new SecureRandom());

        // Create HTTPS Server
        HttpsServer httpsServer = HttpsServer.create(new InetSocketAddress(8443), 0);
        httpsServer.setExecutor(Executors.newFixedThreadPool(10)); // 使用 Thread Pool
        httpsServer.setHttpsConfigurator(new HttpsConfigurator(sslContext) {
            @Override
            public void configure(HttpsParameters params) {
                try {
                    SSLContext context = SSLContext.getDefault(); // 使用默認的 SSLContext
                    SSLEngine engine = context.createSSLEngine();
                    params.setNeedClientAuth(false); //不要求客戶端憑證
                    params.setCipherSuites(engine.getSupportedCipherSuites());
                    params.setProtocols(engine.getSupportedProtocols());

                } catch (Exception ex) {
                    ex.printStackTrace();
                }
            }
        });

        HttpContext context = httpsServer.createContext("/", exchange -> {
            // 取得 HTTP 版本
            String protocol = exchange.getProtocol();
            System.out.println("=== New Request ===");
            System.out.println("HTTP Version: " + protocol);

            // 輸出 Header 資訊
            Headers requestHeaders = exchange.getRequestHeaders();
            System.out.println("Request Headers:");
            for (Map.Entry<String, List<String>> entry : requestHeaders.entrySet()) {
                System.out.println("  " + entry.getKey() + ": " + entry.getValue());
            }

            String response = "Hello, HTTP from Simple Server.";
            exchange.getResponseHeaders().set("Content-Type", "text/plain");
            exchange.sendResponseHeaders(200, response.getBytes().length);
            OutputStream os = exchange.getResponseBody();
            os.write(response.getBytes());
            os.close();
        });

        System.out.println("=== HttpContext Info ===");
        System.out.println("Path: " + context.getPath());
        System.out.println("Server: " + context.getServer());
        System.out.println("Handler: " + context.getHandler());
        System.out.println("Attributes: " + context.getAttributes());
        List<Filter> filters = context.getFilters();
        System.out.println("Filters: " + filters);

        httpsServer.start();
        System.out.println("Server is running on https://localhost:8443");
    }
}
xxxxxxxxxx
 
import com.sun.net.httpserver.Filter;
import com.sun.net.httpserver.Headers;
import com.sun.net.httpserver.HttpContext;
import com.sun.net.httpserver.HttpsConfigurator;
import com.sun.net.httpserver.HttpsParameters;
import com.sun.net.httpserver.HttpsServer;
import javax.net.ssl.*;
​
import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.security.*;
import java.security.cert.X509Certificate;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Executors;
​
public class SimpleHttpServer {
    public static void main(String[] args) throws Exception {
        // 創建一個 KeyStore 來存放憑證
        KeyStore keyStore = KeyStore.getInstance("JKS");
        keyStore.load(null, null); // 載入空 KeyStore
        // 產生自簽名憑證，此處簡化，正式環境請使用正式憑證
        // KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
        // keyPairGenerator.initialize(2048); // 初始化 KeyPairGenerator
        // KeyPair keyPair = keyPairGenerator.generateKeyPair(); // 產生 KeyPair
        KeyPair keyPair = SelfSignedCertificateGenerator.generateRSAKeyPair(2048);
        X509Certificate selfSignedCert = SelfSignedCertificateGenerator.createCertificate(keyPair,
                "CN=localhost, O=my-test-org, L=my-test-loc, ST=my-test-st, C=tw", 365); // 生成自簽名憑證
        keyStore.setKeyEntry("mykey", keyPair.getPrivate(), "password".toCharArray(),
                new X509Certificate[] { selfSignedCert }); // 設定憑證
​
        // 建立 SSL Context
        SSLContext sslContext = SSLContext.getInstance("TLS");
        KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
        keyManagerFactory.init(keyStore, "password".toCharArray());
        TrustManagerFactory trustManagerFactory = TrustManagerFactory
                .getInstance(TrustManagerFactory.getDefaultAlgorithm());
        trustManagerFactory.init(keyStore);
        sslContext.init(keyManagerFactory.getKeyManagers(), trustManagerFactory.getTrustManagers(), new SecureRandom());
​
        // Create HTTPS Server
        HttpsServer httpsServer = HttpsServer.create(new InetSocketAddress(8443), 0);
        httpsServer.setExecutor(Executors.newFixedThreadPool(10)); // 使用 Thread Pool
        httpsServer.setHttpsConfigurator(new HttpsConfigurator(sslContext) {
            @Override
            public void configure(HttpsParameters params) {
                try {
                    SSLContext context = SSLContext.getDefault(); // 使用默認的 SSLContext
                    SSLEngine engine = context.createSSLEngine();
                    params.setNeedClientAuth(false); //不要求客戶端憑證
                    params.setCipherSuites(engine.getSupportedCipherSuites());
                    params.setProtocols(engine.getSupportedProtocols());
​
                } catch (Exception ex) {
                    ex.printStackTrace();
                }
            }
        });
​
        HttpContext context = httpsServer.createContext("/", exchange -> {
            // 取得 HTTP 版本
            String protocol = exchange.getProtocol();
            System.out.println("=== New Request ===");
            System.out.println("HTTP Version: " + protocol);
​
            // 輸出 Header 資訊
            Headers requestHeaders = exchange.getRequestHeaders();
            System.out.println("Request Headers:");
            for (Map.Entry<String, List<String>> entry : requestHeaders.entrySet()) {
                System.out.println("  " + entry.getKey() + ": " + entry.getValue());
            }
​
            String response = "Hello, HTTP from Simple Server.";
            exchange.getResponseHeaders().set("Content-Type", "text/plain");
            exchange.sendResponseHeaders(200, response.getBytes().length);
            OutputStream os = exchange.getResponseBody();
            os.write(response.getBytes());
            os.close();
        });
​
        System.out.println("=== HttpContext Info ===");
        System.out.println("Path: " + context.getPath());
        System.out.println("Server: " + context.getServer());
        System.out.println("Handler: " + context.getHandler());
        System.out.println("Attributes: " + context.getAttributes());
        List<Filter> filters = context.getFilters();
        System.out.println("Filters: " + filters);
​
        httpsServer.start();
        System.out.println("Server is running on https://localhost:8443");
    }
}
​

(5.3) 使用原生 JAVA SE API 建立創建一個 Http2 Client

SimpleHttp2Client.java ：

功能： 建立一個 HTTP/2 客戶端，發送請求到 https://localhost:8443 。
說明：
- 建立 HttpClient 物件時，使用 version(HttpClient.Version.HTTP_2) 強制使用 HTTP/2。
- 為了避免自簽憑證造成連線錯誤，使用了 TrustManager 來信任所有憑證 (這僅限測試用途， 在生產環境中絕對不要這樣做 )。
- 發送請求後，輸出伺服器的回應 body 和 headers。

import java.io.IOException;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.security.SecureRandom;
import java.security.cert.X509Certificate;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;

public class SimpleHttp2Client {

    public static void main(String[] args) throws Exception {
        // Trust all certs(unsafe, only for local testing).
        TrustManager[] trustAllCerts = new TrustManager[] {
                new X509TrustManager() {
                    public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                        return new X509Certificate[0];
                    }

                    public void checkClientTrusted(java.security.cert.X509Certificate[] certs,
                            String authType) {
                    }

                    public void checkServerTrusted(java.security.cert.X509Certificate[] certs,
                            String authType) {
                    }
                }
        };
        SSLContext sslContext = SSLContext.getInstance("TLS");
        sslContext.init(null, trustAllCerts, new SecureRandom());

        HttpClient client = HttpClient.newBuilder()
                .sslContext(sslContext)
                .version(HttpClient.Version.HTTP_2) // 建立 HttpClient 設定 HTTP 版本偏好
                .build();
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://localhost:8443")) // Replace with actual url
                .build();

        try {
            HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
            System.out.println("Response Body: " + response.body());

            System.out.println("Response Headers:");
            response.headers().map().forEach((key, value) -> {
                System.out.println(key + ": " + value);
            });

        } catch (IOException | InterruptedException e) {
            e.printStackTrace();
        }
    }
}
xxxxxxxxxx
 
import java.io.IOException;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.security.SecureRandom;
import java.security.cert.X509Certificate;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
​
public class SimpleHttp2Client {
​
    public static void main(String[] args) throws Exception {
        // Trust all certs(unsafe, only for local testing).
        TrustManager[] trustAllCerts = new TrustManager[] {
                new X509TrustManager() {
                    public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                        return new X509Certificate[0];
                    }
​
                    public void checkClientTrusted(java.security.cert.X509Certificate[] certs,
                            String authType) {
                    }
​
                    public void checkServerTrusted(java.security.cert.X509Certificate[] certs,
                            String authType) {
                    }
                }
        };
        SSLContext sslContext = SSLContext.getInstance("TLS");
        sslContext.init(null, trustAllCerts, new SecureRandom());
​
        HttpClient client = HttpClient.newBuilder()
                .sslContext(sslContext)
                .version(HttpClient.Version.HTTP_2) // 建立 HttpClient 設定 HTTP 版本偏好
                .build();
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://localhost:8443")) // Replace with actual url
                .build();
​
        try {
            HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
            System.out.println("Response Body: " + response.body());
​
            System.out.println("Response Headers:");
            response.headers().map().forEach((key, value) -> {
                System.out.println(key + ": " + value);
            });
​
        } catch (IOException | InterruptedException e) {
            e.printStackTrace();
        }
    }
}
​

(5.4) 讓我們執行以上範例

編譯 SelfSignedCertificateGenerator.java :

$ javac -encoding utf-8 -cp ".;..\lib\*;" SelfSignedCertificateGenerator.java

xxxxxxxxxx
 
$ javac -encoding utf-8 -cp ".;..\lib\*;" SelfSignedCertificateGenerator.java
​

啟動 Local Server ^[1]

$ java -Dfile.encoding=utf-8 -cp ".;..\lib\*;" SimpleHttpServer.java
=== HttpContext Info ===
Path: /
Server: sun.net.httpserver.HttpsServerImpl@1477089c
Handler: SimpleHttpServer$$Lambda$270/0x000002062d14c428@663411de
Attributes: {}
Filters: []
Server is running on https://localhost:8443

xxxxxxxxxx
 
$ java -Dfile.encoding=utf-8 -cp ".;..\lib\*;" SimpleHttpServer.java
=== HttpContext Info ===
Path: /
Server: sun.net.httpserver.HttpsServerImpl@1477089c
Handler: SimpleHttpServer$$Lambda$270/0x000002062d14c428@663411de
Attributes: {}
Filters: []
Server is running on https://localhost:8443
​

執行 Client ^[1:1]

$ java -Dfile.encoding=utf-8 -cp ".;.\lib\*;" SimpleHttp2Client.java
Response Body: Hello, HTTP from Simple Server.
Response Headers:
content-length: [31]
content-type: [text/plain]
date: [Tue, 14 Jan 2025 02:03:32 GMT]

xxxxxxxxxx
 
$ java -Dfile.encoding=utf-8 -cp ".;.\lib\*;" SimpleHttp2Client.java
Response Body: Hello, HTTP from Simple Server.
Response Headers:
content-length: [31]
content-type: [text/plain]
date: [Tue, 14 Jan 2025 02:03:32 GMT]
​

使用 curl 執行請求

$ curl -k --http2 https://localhost:8443 -i -sS
HTTP/1.1 200 OK
Date: Thu, 16 Jan 2025 07:26:55 GMT
Content-type: text/plain
Content-length: 31

Hello, HTTP from Simple Server.

xxxxxxxxxx
 
$ curl -k --http2 https://localhost:8443 -i -sS
HTTP/1.1 200 OK
Date: Thu, 16 Jan 2025 07:26:55 GMT
Content-type: text/plain
Content-length: 31
​
Hello, HTTP from Simple Server.
​

Server 端顯示的資訊

=== New Request ===
HTTP Version: HTTP/1.1
Request Headers:
  Host: [localhost:8443]
  User-agent: [Java-http-client/17.0.13]
  Content-length: [0]
=== New Request ===
HTTP Version: HTTP/1.1
Request Headers:
  Accept: [*/*]
  Host: [localhost:8443]
  User-agent: [curl/7.71.1]

xxxxxxxxxx
 
=== New Request ===
HTTP Version: HTTP/1.1
Request Headers:
  Host: [localhost:8443]
  User-agent: [Java-http-client/17.0.13]
  Content-length: [0]
=== New Request ===
HTTP Version: HTTP/1.1
Request Headers:
  Accept: [*/*]
  Host: [localhost:8443]
  User-agent: [curl/7.71.1]
​

(5.5) Http Server 不支援 HTTP/2

即使你嘗試使用 HttpClient .version(HttpClient.Version.HTTP_2) 或 curl -http2 參數來發送請求，伺服器端仍然顯示 HTTP/1.1 的原因，很可能是客戶端與伺服器之間 TLS 協商的結果，導致雙方最後選擇使用 HTTP/1.1。

問題分析：ALPN (Application-Layer Protocol Negotiation) 缺失
- HTTP/2 的 TLS 連線需要使用 ALPN 擴展，讓客戶端和伺服器在 TLS 握手階段協商應用層協議。如果你的 Java HTTP Server 沒有正確配置 ALPN，它將無法宣告支援 HTTP/2。
- 由於你使用的是 Java 內建的 com.sun.net.httpserver.HttpsServer，它預設並不支援 ALPN。
- 即使客戶端程式碼 (例如 curl -http2 或 Java 內建的 HTTP Client) 要求使用 HTTP/2，但如果伺服器端不支援 ALPN，協商的結果仍會是 HTTP/1.1。

六、使用第三方套件建立 HTTP/2 伺服器

返回目錄

本節將使用 Netty 這個高效能的非同步網路應用程式框架來建立一個支援 HTTP/2 的伺服器。 Netty 提供了對 HTTP/2 的良好支援，並具有非同步、事件驅動、高性能等優點。

下載 Netty 第三方套件: Netty

如果您使用 bash ，以下兩個 jar 檔案需要下載：

資料夾目錄：

.
├── lib
│   ├── bcpkix-jdk18on-1.79.jar
│   ├── bcprov-jdk18on-1.79.jar
│   ├── bcutil-jdk18on-1.79.jar
│   ├── netty-buffer-4.1.116.Final.jar
│   ├── netty-codec-4.1.116.Final.jar
│   ├── netty-codec-http2-4.1.116.Final.jar
│   ├── netty-codec-http-4.1.116.Final.jar
│   ├── netty-common-4.1.116.Final.jar
│   ├── netty-handler-4.1.116.Final.jar
│   ├── netty-transport-4.1.116.Final.jar
│   ├── netty-transport-native-epoll-4.1.116.Final.jar
│   └── netty-transport-native-unix-common-4.1.116.Final.jar
└── src
    ├── SimpleHttp2Client.java
    └── SimpleHttp2Server.java

xxxxxxxxxx
 
.
├── lib
│   ├── bcpkix-jdk18on-1.79.jar
│   ├── bcprov-jdk18on-1.79.jar
│   ├── bcutil-jdk18on-1.79.jar
│   ├── netty-buffer-4.1.116.Final.jar
│   ├── netty-codec-4.1.116.Final.jar
│   ├── netty-codec-http2-4.1.116.Final.jar
│   ├── netty-codec-http-4.1.116.Final.jar
│   ├── netty-common-4.1.116.Final.jar
│   ├── netty-handler-4.1.116.Final.jar
│   ├── netty-transport-4.1.116.Final.jar
│   ├── netty-transport-native-epoll-4.1.116.Final.jar
│   └── netty-transport-native-unix-common-4.1.116.Final.jar
└── src
    ├── SimpleHttp2Client.java
    └── SimpleHttp2Server.java
​

Netty 的核心概念

在深入程式碼之前，我們先來了解一下 Netty 的幾個核心概念，這有助於我們理解程式碼的結構：

EventLoopGroup: 負責處理網路事件的執行緒池，Netty 使用非同步 I/O，它包含一或多個 EventLoop ，每個 EventLoop 負責處理一個或多個 Channel 上的 I/O 事件。
- 在我們的範例中， bossGroup 負責接收新的連線， workerGroup 負責處理連線上的 I/O。
Channel: 表示一個網路連線的抽象，提供讀取、寫入、關閉等操作。
- NioServerSocketChannel 是 Netty 用於接收新的 TCP 連線的 Channel 實現。
ChannelPipeline: Netty 的處理器鍊，資料會在 ChannelPipeline 中的處理器 ( ChannelHandler ) 之間傳遞。
- 每個 ChannelHandler 可以修改、過濾、攔截、處理資料。
ChannelHandler: Netty 中處理 I/O 事件的元件，例如 SslHandler 處理 SSL/TLS 加密， LoggingHandler 輸出日誌。
- 我們自訂的 SimpleHttp2ServerHandler 是一個 ChannelHandler ，用於處理 HTTP/2 請求。
Http2FrameCodec: Netty 提供的編碼器和解碼器，將底層的二進位資料轉換為 HTTP/2 框架，方便上層的 Handler 處理。
Http2MultiplexHandler: Netty 提供的處理器，用於處理多個 HTTP/2 串流，它將同一個連線上的多個串流分發到不同的 Channel 上處理。
ALPN (Application-Layer Protocol Negotiation): TLS 的一個擴展，允許客戶端和伺服器在 TLS 握手階段協商使用哪種應用層協定 (例如 HTTP/1.1 或 HTTP/2)。

範例： HTTP/2 Server

SimpleHttp2Server.java ：

功能： 使用 Netty 框架建立一個支援 HTTP/2 的 HTTPS 伺服器。
說明：
- 使用 SelfSignedCertificate 生成自簽憑證，用於 HTTPS 連線。
- 透過 SslContextBuilder 配置 SSL 上下文，並啟用 ALPN 來協商 HTTP/2 協議。
- 使用 ServerBootstrap 設定 Netty 伺服器，包括設定 EventLoopGroup 和 Channel 類型。
- 透過 ChannelInitializer 初始化 Channel Pipeline，加入 SslHandler、LoggingHandler、Http2FrameCodec 和 Http2MultiplexHandler 等處理器。
- Http2FrameCodec 負責編碼和解碼 HTTP/2 框架，Http2MultiplexHandler 負責處理多個 HTTP/2 串流。
- 使用自訂的 SimpleHttp2ServerHandler 處理 HTTP/2 請求，並回覆簡單的 "Hello World" 訊息。
Netty ：一個高性能、非同步事件驅動的網路應用程式框架，用於快速開發高效能的網路伺服器和客戶端。
ALPN (Application-Layer Protocol Negotiation) : TLS 的一個擴展，允許客戶端和伺服器在 TLS 握手階段協商使用哪種應用層協定 (例如 HTTP/1.1 或 HTTP/2)。

import io.netty.bootstrap.ServerBootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.*;
import io.netty.handler.codec.http2.*;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.ssl.*;
import io.netty.handler.ssl.util.SelfSignedCertificate;
import io.netty.util.CharsetUtil;

import java.util.concurrent.TimeUnit;

public class SimpleHttp2Server {

    static final int PORT = 8443; // 定義伺服器監聽的端口

    public static void main(String[] args) throws Exception {
        // 1. 配置 SSL 上下文 (SSL Context)
        SelfSignedCertificate ssc = new SelfSignedCertificate(); // 產生自簽憑證，用於 HTTPS
        SslContext sslCtx = SslContextBuilder.forServer(ssc.certificate(), ssc.privateKey()) // 建立 SSL 上下文
                .applicationProtocolConfig(new ApplicationProtocolConfig( // 設定應用程式協定設定
                        ApplicationProtocolConfig.Protocol.ALPN, // 使用 ALPN (Application-Layer Protocol Negotiation) 進行協商
                        ApplicationProtocolConfig.SelectorFailureBehavior.NO_ADVERTISE, // 如果無法協商，則不發佈協定
                        ApplicationProtocolConfig.SelectedListenerFailureBehavior.ACCEPT, // 如果協商失敗，則接受連線
                        ApplicationProtocolNames.HTTP_2, // 支援 HTTP/2
                        ApplicationProtocolNames.HTTP_1_1)) // 支援 HTTP/1.1
                .build(); // 建立 SslContext 物件

        // 2. 配置 Netty Server
        EventLoopGroup bossGroup = new NioEventLoopGroup(1); // 負責接受連線的 EventLoopGroup (通常只有一個執行緒)
        EventLoopGroup workerGroup = new NioEventLoopGroup(); // 負責處理連線 I/O 的 EventLoopGroup (執行緒池)

        try {
            ServerBootstrap b = new ServerBootstrap(); // 建立 ServerBootstrap 物件
            b.option(ChannelOption.SO_BACKLOG, 1024); // 設定 TCP 連線的 Backlog 大小
            b.group(bossGroup, workerGroup) // 設定 EventLoopGroup
                    .channel(NioServerSocketChannel.class) // 使用 NIO 的 ServerSocketChannel
                    .childHandler(new ChannelInitializer<Channel>() { // 設定子連線的 Handler

                        @Override
                        protected void initChannel(Channel ch) throws Exception {
                            ChannelPipeline p = ch.pipeline(); // 取得 Channel 的 ChannelPipeline
                            p.addLast(sslCtx.newHandler(ch.alloc())); // 將 SslHandler 加入 ChannelPipeline，處理 SSL/TLS 加密
                            p.addLast(new LoggingHandler(LogLevel.INFO)); // 加入 LoggingHandler，輸出日誌

                            // 3. 建立 HTTP/2 編碼器 (Http2FrameCodec)
                            final Http2FrameCodec codec = Http2FrameCodecBuilder.forServer()
                                    .gracefulShutdownTimeoutMillis(10000) // 設定優雅關閉的逾時時間
                                    .initialSettings( // 設定 HTTP/2 的初始設定
                                            new Http2Settings()
                                                    .headerTableSize(4096) // 設定標頭表格大小
                                                    .maxConcurrentStreams(Integer.MAX_VALUE) // 設定最大並行串流數量
                                                    .initialWindowSize(1 << 23) // 設定初始視窗大小
                                                    .maxFrameSize(1 << 23) // 設定最大框架大小
                                                    .maxHeaderListSize((1 << 15) * 2)) // 設定最大標頭列表大小
                                    .build(); // 建立 Http2FrameCodec 物件

                            // 4. 建立 HTTP/2 多工處理器 (Http2MultiplexHandler)
                            final Http2MultiplexHandler handler = new Http2MultiplexHandler(
                                    new ChannelInitializer<Channel>() { // 設定子串流的 Handler

                                        @Override
                                        protected void initChannel(Channel ch) throws Exception {
                                            final ChannelPipeline p = ch.pipeline(); // 取得子串流的 ChannelPipeline
                                            p.addLast(new SimpleHttp2ServerHandler()); // 將自訂的 SimpleHttp2ServerHandler 加入 ChannelPipeline
                                        }

                                    });

                            // 5. 將 HTTP/2 編碼器和處理器加入 ChannelPipeline
                            p.addLast(codec) // 加入 Http2FrameCodec，用於編碼和解碼 HTTP/2 框架
                                    .addLast(handler); // 加入 Http2MultiplexHandler，用於處理多個 HTTP/2 串流
                        }

                    });

            // 6. 綁定伺服器端口並開始監聽
            ChannelFuture f = b.bind(PORT).sync(); // 綁定端口，並同步等待綁定完成

            String link = String.format( // 建立伺服器連結字串
                    "https://localhost:%d",
                    PORT);
            System.err.println(link); // 輸出伺服器連結

            // 7. 等待伺服器 Socket 關閉
            f.channel().closeFuture().sync(); // 同步等待 Channel 關閉
        } catch (Exception e) {
            e.printStackTrace(); // 印出例外堆疊追蹤
        } finally {
            // 8. 優雅關閉 EventLoopGroup
            bossGroup.shutdownGracefully(0, 5, TimeUnit.SECONDS); // 優雅關閉 bossGroup，等待 5 秒
            workerGroup.shutdownGracefully(0, 5, TimeUnit.SECONDS); // 優雅關閉 workerGroup，等待 5 秒
        }
    }

    // 9. 自訂的 HTTP/2 伺服器處理器
    static class SimpleHttp2ServerHandler extends ChannelDuplexHandler {

        final ByteBuf RESPONSE_BYTES = Unpooled.unreleasableBuffer( // 建立回應的 ByteBuf，不可釋放
                Unpooled.copiedBuffer("Hello World", CharsetUtil.UTF_8)).asReadOnly(); // 複製 "Hello World" 字串到 ByteBuf 中，並設為唯讀

        @Override
        public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
            // 10. 處理 HTTP/2 框架
            if (msg instanceof Http2HeadersFrame) { // 如果是 Http2HeadersFrame
                Http2HeadersFrame msgHeader = (Http2HeadersFrame) msg; // 強制轉換為 Http2HeadersFrame
                if (msgHeader.isEndStream()) { // 如果是串流結束的標頭框架
                    System.out.println("-hhhhh"); // 印出訊息
                    writeData(ctx, msgHeader.stream()); // 回應資料
                } else {
                    System.out.println("hhhhh"); // 印出訊息
                }
            } else if (msg instanceof Http2DataFrame) { // 如果是 Http2DataFrame
                Http2DataFrame msgData = (Http2DataFrame) msg; // 強制轉換為 Http2DataFrame
                if (msgData.isEndStream()) { // 如果是串流結束的資料框架
                    System.out.println("-ddddd"); // 印出訊息
                    writeData(ctx, msgData.stream()); // 回應資料
                } else {
                    System.out.println("ddddd"); // 印出訊息
                }
            } else {
                super.channelRead(ctx, msg); // 如果不是 HTTP/2 框架，則傳遞到下一個 Handler 處理
            }
        }

        // 11. 回應資料
        private void writeData(ChannelHandlerContext ctx, Http2FrameStream stream) {
            ByteBuf content = ctx.alloc().buffer(); // 建立可寫的 ByteBuf
            content.writeBytes(RESPONSE_BYTES.duplicate()); // 複製回應內容到 ByteBuf
            Http2Headers headers = new DefaultHttp2Headers().status(HttpResponseStatus.OK.codeAsText()) // 建立回應標頭
                    .add("t1", "ttt") // 加入自訂標頭
                    .add("t2", "tttt"); // 加入自訂標頭
            ctx.write(new DefaultHttp2HeadersFrame(headers).stream(stream)); // 發送標頭框架
            ctx.write(new DefaultHttp2DataFrame(content, true).stream(stream)); // 發送資料框架
        }
    }
}
xxxxxxxxxx
 
import io.netty.bootstrap.ServerBootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.*;
import io.netty.handler.codec.http2.*;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.ssl.*;
import io.netty.handler.ssl.util.SelfSignedCertificate;
import io.netty.util.CharsetUtil;
​
import java.util.concurrent.TimeUnit;
​
public class SimpleHttp2Server {
​
    static final int PORT = 8443; // 定義伺服器監聽的端口
​
    public static void main(String[] args) throws Exception {
        // 1. 配置 SSL 上下文 (SSL Context)
        SelfSignedCertificate ssc = new SelfSignedCertificate(); // 產生自簽憑證，用於 HTTPS
        SslContext sslCtx = SslContextBuilder.forServer(ssc.certificate(), ssc.privateKey()) // 建立 SSL 上下文
                .applicationProtocolConfig(new ApplicationProtocolConfig( // 設定應用程式協定設定
                        ApplicationProtocolConfig.Protocol.ALPN, // 使用 ALPN (Application-Layer Protocol Negotiation) 進行協商
                        ApplicationProtocolConfig.SelectorFailureBehavior.NO_ADVERTISE, // 如果無法協商，則不發佈協定
                        ApplicationProtocolConfig.SelectedListenerFailureBehavior.ACCEPT, // 如果協商失敗，則接受連線
                        ApplicationProtocolNames.HTTP_2, // 支援 HTTP/2
                        ApplicationProtocolNames.HTTP_1_1)) // 支援 HTTP/1.1
                .build(); // 建立 SslContext 物件
​
        // 2. 配置 Netty Server
        EventLoopGroup bossGroup = new NioEventLoopGroup(1); // 負責接受連線的 EventLoopGroup (通常只有一個執行緒)
        EventLoopGroup workerGroup = new NioEventLoopGroup(); // 負責處理連線 I/O 的 EventLoopGroup (執行緒池)
​
        try {
            ServerBootstrap b = new ServerBootstrap(); // 建立 ServerBootstrap 物件
            b.option(ChannelOption.SO_BACKLOG, 1024); // 設定 TCP 連線的 Backlog 大小
            b.group(bossGroup, workerGroup) // 設定 EventLoopGroup
                    .channel(NioServerSocketChannel.class) // 使用 NIO 的 ServerSocketChannel
                    .childHandler(new ChannelInitializer<Channel>() { // 設定子連線的 Handler
​
                        @Override
                        protected void initChannel(Channel ch) throws Exception {
                            ChannelPipeline p = ch.pipeline(); // 取得 Channel 的 ChannelPipeline
                            p.addLast(sslCtx.newHandler(ch.alloc())); // 將 SslHandler 加入 ChannelPipeline，處理 SSL/TLS 加密
                            p.addLast(new LoggingHandler(LogLevel.INFO)); // 加入 LoggingHandler，輸出日誌
​
                            // 3. 建立 HTTP/2 編碼器 (Http2FrameCodec)
                            final Http2FrameCodec codec = Http2FrameCodecBuilder.forServer()
                                    .gracefulShutdownTimeoutMillis(10000) // 設定優雅關閉的逾時時間
                                    .initialSettings( // 設定 HTTP/2 的初始設定
                                            new Http2Settings()
                                                    .headerTableSize(4096) // 設定標頭表格大小
                                                    .maxConcurrentStreams(Integer.MAX_VALUE) // 設定最大並行串流數量
                                                    .initialWindowSize(1 << 23) // 設定初始視窗大小
                                                    .maxFrameSize(1 << 23) // 設定最大框架大小
                                                    .maxHeaderListSize((1 << 15) * 2)) // 設定最大標頭列表大小
                                    .build(); // 建立 Http2FrameCodec 物件
​
                            // 4. 建立 HTTP/2 多工處理器 (Http2MultiplexHandler)
                            final Http2MultiplexHandler handler = new Http2MultiplexHandler(
                                    new ChannelInitializer<Channel>() { // 設定子串流的 Handler
​
                                        @Override
                                        protected void initChannel(Channel ch) throws Exception {
                                            final ChannelPipeline p = ch.pipeline(); // 取得子串流的 ChannelPipeline
                                            p.addLast(new SimpleHttp2ServerHandler()); // 將自訂的 SimpleHttp2ServerHandler 加入 ChannelPipeline
                                        }
​
                                    });
​
                            // 5. 將 HTTP/2 編碼器和處理器加入 ChannelPipeline
                            p.addLast(codec) // 加入 Http2FrameCodec，用於編碼和解碼 HTTP/2 框架
                                    .addLast(handler); // 加入 Http2MultiplexHandler，用於處理多個 HTTP/2 串流
                        }
​
                    });
​
            // 6. 綁定伺服器端口並開始監聽
            ChannelFuture f = b.bind(PORT).sync(); // 綁定端口，並同步等待綁定完成
​
            String link = String.format( // 建立伺服器連結字串
                    "https://localhost:%d",
                    PORT);
            System.err.println(link); // 輸出伺服器連結
​
            // 7. 等待伺服器 Socket 關閉
            f.channel().closeFuture().sync(); // 同步等待 Channel 關閉
        } catch (Exception e) {
            e.printStackTrace(); // 印出例外堆疊追蹤
        } finally {
            // 8. 優雅關閉 EventLoopGroup
            bossGroup.shutdownGracefully(0, 5, TimeUnit.SECONDS); // 優雅關閉 bossGroup，等待 5 秒
            workerGroup.shutdownGracefully(0, 5, TimeUnit.SECONDS); // 優雅關閉 workerGroup，等待 5 秒
        }
    }
​
    // 9. 自訂的 HTTP/2 伺服器處理器
    static class SimpleHttp2ServerHandler extends ChannelDuplexHandler {
​
        final ByteBuf RESPONSE_BYTES = Unpooled.unreleasableBuffer( // 建立回應的 ByteBuf，不可釋放
                Unpooled.copiedBuffer("Hello World", CharsetUtil.UTF_8)).asReadOnly(); // 複製 "Hello World" 字串到 ByteBuf 中，並設為唯讀
​
        @Override
        public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
            // 10. 處理 HTTP/2 框架
            if (msg instanceof Http2HeadersFrame) { // 如果是 Http2HeadersFrame
                Http2HeadersFrame msgHeader = (Http2HeadersFrame) msg; // 強制轉換為 Http2HeadersFrame
                if (msgHeader.isEndStream()) { // 如果是串流結束的標頭框架
                    System.out.println("-hhhhh"); // 印出訊息
                    writeData(ctx, msgHeader.stream()); // 回應資料
                } else {
                    System.out.println("hhhhh"); // 印出訊息
                }
            } else if (msg instanceof Http2DataFrame) { // 如果是 Http2DataFrame
                Http2DataFrame msgData = (Http2DataFrame) msg; // 強制轉換為 Http2DataFrame
                if (msgData.isEndStream()) { // 如果是串流結束的資料框架
                    System.out.println("-ddddd"); // 印出訊息
                    writeData(ctx, msgData.stream()); // 回應資料
                } else {
                    System.out.println("ddddd"); // 印出訊息
                }
            } else {
                super.channelRead(ctx, msg); // 如果不是 HTTP/2 框架，則傳遞到下一個 Handler 處理
            }
        }
​
        // 11. 回應資料
        private void writeData(ChannelHandlerContext ctx, Http2FrameStream stream) {
            ByteBuf content = ctx.alloc().buffer(); // 建立可寫的 ByteBuf
            content.writeBytes(RESPONSE_BYTES.duplicate()); // 複製回應內容到 ByteBuf
            Http2Headers headers = new DefaultHttp2Headers().status(HttpResponseStatus.OK.codeAsText()) // 建立回應標頭
                    .add("t1", "ttt") // 加入自訂標頭
                    .add("t2", "tttt"); // 加入自訂標頭
            ctx.write(new DefaultHttp2HeadersFrame(headers).stream(stream)); // 發送標頭框架
            ctx.write(new DefaultHttp2DataFrame(content, true).stream(stream)); // 發送資料框架
        }
    }
}
​

啟動伺服器：

$ java -Dfile.encoding=utf-8 -cp ".;..\lib\*;" SimpleHttp2Server.java
https://localhost:8443

xxxxxxxxxx
 
$ java -Dfile.encoding=utf-8 -cp ".;..\lib\*;" SimpleHttp2Server.java
https://localhost:8443
​

執行 Client

$ java -Dfile.encoding=utf-8 -cp ".;.\lib\*;" SimpleHttp2Client.java
Response Body: Hello World
Response Headers:
:status: [200]
t1: [ttt]
t2: [tttt]

xxxxxxxxxx
 
$ java -Dfile.encoding=utf-8 -cp ".;.\lib\*;" SimpleHttp2Client.java
Response Body: Hello World
Response Headers:
:status: [200]
t1: [ttt]
t2: [tttt]
​

使用 curl 執行請求

$ curl -k --http2 https://localhost:8443 -i -sS
HTTP/2 200
t1: ttt
t2: tttt

Hello World

xxxxxxxxxx
 
$ curl -k --http2 https://localhost:8443 -i -sS
HTTP/2 200
t1: ttt
t2: tttt
​
Hello World
​

Server 端顯示的資訊

1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler write
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] WRITE: 39B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 1e 04 00 00 00 00 00 00 01 00 00 10 00 00 |................|
|00000010| 03 7f ff ff ff 00 04 00 80 00 00 00 05 00 80 00 |................|
|00000020| 00 00 06 00 01 00 00                            |.......         |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler write
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] WRITE: 13B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 04 08 00 00 00 00 00 00 fe 00 02          |.............   |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler flush
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] FLUSH
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelRegistered
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] REGISTERED
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelActive
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] ACTIVE
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler flush
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] FLUSH
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelReadComplete
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ COMPLETE
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler flush
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] FLUSH
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler userEventTriggered
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] USER_EVENT: SslHandshakeCompletionEvent(SUCCESS)
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelRead
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ: 24B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 50 52 49 20 2a 20 48 54 54 50 2f 32 2e 30 0d 0a |PRI * HTTP/2.0..|
|00000010| 0d 0a 53 4d 0d 0a 0d 0a                         |..SM....        |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelRead
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ: 27B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 12 04 00 00 00 00 00 00 03 00 00 00 64 00 |..............d.|
|00000010| 04 02 00 00 00 00 02 00 00 00 00                |...........     |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler write
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] WRITE: 9B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 00 04 01 00 00 00 00                      |.........       |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelRead
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ: 13B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 04 08 00 00 00 00 00 01 ff 00 01          |.............   |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelRead
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ: 39B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 1e 01 05 00 00 00 01 82 84 87 41 8a a0 e4 |............A...|
|00000010| 1d 13 9d 09 b8 f3 4d 33 7a 88 25 b6 50 c3 ab ba |......M3z.%.P...|
|00000020| 15 c3 53 03 2a 2f 2a                            |..S.*/*         |
+--------+-------------------------------------------------+----------------+
-hhhhh
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler write
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] WRITE: 9B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 12 01 04 00 00 00 01                      |.........       |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler write
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] WRITE: 18B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 88 40 02 74 31 03 74 74 74 40 02 74 32 04 74 74 |.@.t1.ttt@.t2.tt|
|00000010| 74 74                                           |tt              |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelReadComplete
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ COMPLETE
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler write
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] WRITE: 9B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 0b 00 01 00 00 00 01                      |.........       |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler write
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] WRITE: 11B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 48 65 6c 6c 6f 20 57 6f 72 6c 64                |Hello World     |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler flush
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] FLUSH
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler flush
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] FLUSH
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler flush
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] FLUSH
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelRead
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ: 9B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 00 04 01 00 00 00 00                      |.........       |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler userEventTriggered
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] USER_EVENT: SslCloseCompletionEvent(SUCCESS)
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelReadComplete
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ COMPLETE
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler flush
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] FLUSH
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelReadComplete
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ COMPLETE
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler flush
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] FLUSH
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelInactive
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 ! R:/[0:0:0:0:0:0:0:1]:14022] INACTIVE
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelUnregistered
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 ! R:/[0:0:0:0:0:0:0:1]:14022] UNREGISTERED

xxxxxxxxxx
 
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler write
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] WRITE: 39B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 1e 04 00 00 00 00 00 00 01 00 00 10 00 00 |................|
|00000010| 03 7f ff ff ff 00 04 00 80 00 00 00 05 00 80 00 |................|
|00000020| 00 00 06 00 01 00 00                            |.......         |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler write
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] WRITE: 13B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 04 08 00 00 00 00 00 00 fe 00 02          |.............   |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler flush
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] FLUSH
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelRegistered
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] REGISTERED
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelActive
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] ACTIVE
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler flush
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] FLUSH
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelReadComplete
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ COMPLETE
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler flush
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] FLUSH
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler userEventTriggered
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] USER_EVENT: SslHandshakeCompletionEvent(SUCCESS)
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelRead
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ: 24B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 50 52 49 20 2a 20 48 54 54 50 2f 32 2e 30 0d 0a |PRI * HTTP/2.0..|
|00000010| 0d 0a 53 4d 0d 0a 0d 0a                         |..SM....        |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelRead
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ: 27B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 12 04 00 00 00 00 00 00 03 00 00 00 64 00 |..............d.|
|00000010| 04 02 00 00 00 00 02 00 00 00 00                |...........     |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler write
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] WRITE: 9B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 00 04 01 00 00 00 00                      |.........       |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelRead
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ: 13B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 04 08 00 00 00 00 00 01 ff 00 01          |.............   |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelRead
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ: 39B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 1e 01 05 00 00 00 01 82 84 87 41 8a a0 e4 |............A...|
|00000010| 1d 13 9d 09 b8 f3 4d 33 7a 88 25 b6 50 c3 ab ba |......M3z.%.P...|
|00000020| 15 c3 53 03 2a 2f 2a                            |..S.*/*         |
+--------+-------------------------------------------------+----------------+
-hhhhh
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler write
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] WRITE: 9B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 12 01 04 00 00 00 01                      |.........       |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler write
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] WRITE: 18B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 88 40 02 74 31 03 74 74 74 40 02 74 32 04 74 74 |.@.t1.ttt@.t2.tt|
|00000010| 74 74                                           |tt              |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelReadComplete
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ COMPLETE
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler write
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] WRITE: 9B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 0b 00 01 00 00 00 01                      |.........       |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler write
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] WRITE: 11B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 48 65 6c 6c 6f 20 57 6f 72 6c 64                |Hello World     |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler flush
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] FLUSH
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler flush
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] FLUSH
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler flush
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] FLUSH
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelRead
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ: 9B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 00 00 00 04 01 00 00 00 00                      |.........       |
+--------+-------------------------------------------------+----------------+
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler userEventTriggered
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] USER_EVENT: SslCloseCompletionEvent(SUCCESS)
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelReadComplete
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ COMPLETE
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler flush
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] FLUSH
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelReadComplete
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] READ COMPLETE
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler flush
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 - R:/[0:0:0:0:0:0:0:1]:14022] FLUSH
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelInactive
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 ! R:/[0:0:0:0:0:0:0:1]:14022] INACTIVE
1??16, 2025 3:43:36 銝? io.netty.handler.logging.LoggingHandler channelUnregistered
鞈?: [id: 0x3130d797, L:/[0:0:0:0:0:0:0:1]:8443 ! R:/[0:0:0:0:0:0:0:1]:14022] UNREGISTERED
​

Netty官方有提供不少的範例可供學習，例如： http2-helloworld-server ，在pipeline中使用了升級 UpgradeCodecFactory 的方式處理 HTTP/1.1 與 HTTP/2，有興趣可以下載源碼執行看看。

七、Java 12 ~ 17：持續的改進與優化

返回目錄

Java 12 至 17 主要在 HTTP Client API 的基礎上進行了改進和優化， 這些改進主要集中在性能、穩定性和易用性方面，而非核心架構的變動。

性能優化： 在非同步請求處理方面進行了性能提升，使得處理大量並行請求時，程式的效率更高，資源利用率也會更好。
bug 修復： 針對先前版本發現的 bug 進行了修復，提高了 API 的穩定性和可靠性。
新的特性：
- 增加了對 WebSocket 的支援 (Java 11 起) 以及後續版本的完善。
- 其他細節性的改進，例如 API 的易用性、錯誤處理機制、以及對特定邊緣情況的處理等方面的提升，使得 HTTP Client API 更為穩定和易用。

在 Java 12 到 17 期間，HTTP Client API 的核心功能和架構沒有發生重大改變，主要是針對細節方面進行了完善，因此開發者可以繼續使用 java.net.http 包下的類別來進行 HTTP/2 通訊，並享受性能提升和 bug 修復帶來的好處，而無需擔心 API 的不兼容性問題。

架構圖 (Java 12-17 HTTP Client API):

八、總結

返回目錄

從 Java 7 的第三方函式庫到 Java 17 的原生支援，Java 在 HTTP/2 的發展過程中走過了漫長的道路。Java 9 引入的 HTTP Client API 作為關鍵的轉折點，而 Java 11 將其納入標準 API，使得開發者可以更便捷、高效地使用 HTTP/2。 Java 12 至 17 在此基礎上進行了持續的優化和改進，主要集中在性能、穩定性和易用性方面，而非核心架構的變動。 這使得 API 的整體表現更為出色，開發者可以更放心地使用 java.net.http 包進行 HTTP/2 通訊。

總結來說，Java 對 HTTP/2 的支援是一個逐步發展的過程，從最初依賴第三方函式庫，到後來提供原生的客戶端 API，再到後續的持續改進，每一步都為開發者提供了更為便捷高效的工具。值得注意的是，Java 原生 API 僅提供 HTTP/2 Client 的支援，若要建立 HTTP/2 Server 仍需要依賴第三方套件 (如 Netty)。開發者應當充分利用這些新特性，以及如 Netty 這類的第三方函式庫，構建更加現代化和高效的網路應用程式。

返回目錄

附錄

返回目錄

JEP 330（Launch Single-File Source-Code Programs）是 Java 11 引入的一個重要特性，它允許開發者直接使用 java 指令執行單一檔案的 Java 原始碼（ .java 檔案），而無需事先編譯成 .class 檔案。 ↩︎ ↩︎

網頁

Blogger 站內搜尋

2025年1月18日星期六

JAVA 7 to 17 Http2

一、前言

目錄

二、Java 7/8：HTTP/2 的萌芽

三、Java 9：HTTP/2 客戶端 API 的曙光

四、Java 11：HTTP Client API 的正式加入

五、HTTP Server 和 HTTP/2 Client 範例

六、使用第三方套件建立 HTTP/2 伺服器

七、Java 12 ~ 17：持續的改進與優化

八、總結

附錄

沒有留言:

張貼留言

網頁

Blogger 站內搜尋

2025年1月18日 星期六

JAVA 7 to 17 Http2

一、前言

目錄

二、Java 7/8：HTTP/2 的萌芽

三、Java 9：HTTP/2 客戶端 API 的曙光

四、Java 11：HTTP Client API 的正式加入

五、HTTP Server 和 HTTP/2 Client 範例

六、使用第三方套件建立 HTTP/2 伺服器

七、Java 12 ~ 17：持續的改進與優化

八、總結

附錄

沒有留言:

張貼留言

2025年1月18日星期六