java17使用http2的示例

Java 17 中已经内置支持 HTTP/2，可以使用 JDK 自带的 HttpServer 来创建一个 HTTP/2 的服务端。下面是一个简单的示例代码：

import com.sun.net.httpserver.HttpServer;
import com.sun.net.httpserver.HttpsConfigurator;
import com.sun.net.httpserver.HttpsServer;
import com.sun.net.httpserver.HttpsParameters;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManagerFactory;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.InetSocketAddress;
import java.security.KeyStore;

public class Http2Server {

    public static void main(String[] args) throws Exception {
        int port = 8443;
        String keystorePath = "/path/to/keystore.jks";
        String keystorePassword = "password";

        SSLContext sslContext = SSLContext.getInstance("TLS");

        // Load the keystore
        KeyStore keyStore = KeyStore.getInstance("JKS");
        InputStream inputStream = new FileInputStream(keystorePath);
        keyStore.load(inputStream, keystorePassword.toCharArray());

        // Initialize the key manager factory
        KeyManagerFactory kmf = KeyManagerFactory.getInstance("SunX509");
        kmf.init(keyStore, keystorePassword.toCharArray());

        // Initialize the trust manager factory
        TrustManagerFactory tmf = TrustManagerFactory.getInstance("SunX509");
        tmf.init(keyStore);

        // Initialize the SSL context
        sslContext.init(kmf.getKeyManagers(), tmf.getTrustManagers(), null);

        // Create the HTTPS server
        HttpsServer httpsServer = HttpsServer.create(new InetSocketAddress(port), 0);
        httpsServer.setHttpsConfigurator(new HttpsConfigurator(sslContext) {
            public void configure(HttpsParameters params) {
                try {
                    // Initialize the SSL context
                    SSLContext sslContext = SSLContext.getDefault();
                    SSLEngine engine = sslContext.createSSLEngine();
                    params.setNeedClientAuth(false);
                    params.setCipherSuites(engine.getEnabledCipherSuites());
                    params.setProtocols(engine.getEnabledProtocols());

                    // Get the default parameters
                    SSLParameters defaultSSLParameters = sslContext.getDefaultSSLParameters();
                    params.setSSLParameters(defaultSSLParameters);
                } catch (Exception ex) {
                    ex.printStackTrace();
                }
            }
        });

        // Create the HTTP server
        HttpServer httpServer = HttpServer.create(new InetSocketAddress(port), 0);

        // Set the HTTP handler
        httpServer.createContext("/", new MyHttpHandler());

        // Set the HTTPS handler
        httpsServer.createContext("/", new MyHttpsHandler());

        // Start the servers
        httpServer.start();
        httpsServer.start();

        System.out.println("Server started on port " + port);
    }

    static class MyHttpHandler implements HttpHandler {
        public void handle(HttpExchange exchange) throws IOException {
            String response = "Hello, HTTP/2!";
            exchange.sendResponseHeaders(200, response.getBytes().length);
            OutputStream os = exchange.getResponseBody();
            os.write(response.getBytes());
            os.close();
        }
    }

    static class MyHttpsHandler implements HttpsHandler {
        public void handle(HttpExchange exchange) throws IOException {
            String response = "Hello, HTTPS/2!";
            exchange.sendResponseHeaders(200, response.getBytes().length);
            OutputStream os = exchange.getResponseBody();
            os.write(response.getBytes());
            os.close();
        }
    }
}

在该示例中，我们使用 HttpServer 和 HttpsServer 类来创建一个 HTTP/2 的服务端。我们通过加载一个 keystore 来设置 HTTPS 服务的 SSL 上下文，并且将 HTTP 和 HTTPS 的请求分别交给 MyHttpHandler 和 MyHttpsHandler 来处理。当收到请求时，这两个处理器会分别返回 "Hello, HTTP/2!" 和 "Hello, HTTPS/2!" 的响应。