在 Java 中建立 HTTP 代理伺服器

package delftstack;

import java.io.*;
import java.net.*;
public class Proxy_Server {
  public static void main(String[] args) throws IOException {
    try {
      String Proxy_Host = "Our Proxy Server";
      int Remote_Port = 1025;
      int Local_Port = 1026;
      // Printing the start-up message
      System.out.println(
          "Starting proxy for " + Proxy_Host + ":" + Remote_Port + " on port " + Local_Port);
      // start the server
      Run_Server(Proxy_Host, Remote_Port, Local_Port);
    } catch (Exception e) {
      System.err.println(e);
    }
  }

  public static void Run_Server(String Proxy_Host, int Remote_Port, int Local_Port)
      throws IOException {
    // Create a ServerSocket to listen connections
    ServerSocket Server_Socket = new ServerSocket(Local_Port);
    final byte[] Request = new byte[1024];
    byte[] Reply = new byte[4096];
    while (true) {
      Socket Socket_Client = null, Socket_Server = null;
      try {
        // wait for a connection on the local port
        Socket_Client = Server_Socket.accept();
        final InputStream InputStreamClient = Socket_Client.getInputStream();
        final OutputStream OutputStreamClient = Socket_Client.getOutputStream();

        // Create the connection to the real server.
        try {
          Socket_Server = new Socket(Proxy_Host, Remote_Port);
        } catch (IOException e) {
          PrintWriter out = new PrintWriter(OutputStreamClient);
          out.print("The Proxy Server could not connect to " + Proxy_Host + ":" + Remote_Port
              + ":\n" + e + "\n");
          out.flush();
          Socket_Client.close();
          continue;
        }

        final InputStream InputStreamServer = Socket_Server.getInputStream();
        final OutputStream OutputStreamServer = Socket_Server.getOutputStream();

        // The thread to read the client's requests and to pass them
        Thread New_Thread = new Thread() {
          public void run() {
            int Bytes_Read;
            try {
              while ((Bytes_Read = InputStreamClient.read(Request)) != -1) {
                OutputStreamServer.write(Request, 0, Bytes_Read);
                OutputStreamServer.flush();
              }
            } catch (IOException e) {
            }

            // Close the connections
            try {
              OutputStreamServer.close();
            } catch (IOException e) {
            }
          }
        };

        // client-to-server request thread
        New_Thread.start();
        // Read server's responses and pass them to the client.
        int Bytes_Read;
        try {
          while ((Bytes_Read = InputStreamServer.read(Reply)) != -1) {
            OutputStreamClient.write(Reply, 0, Bytes_Read);
            OutputStreamClient.flush();
          }
        } catch (IOException e) {
        }
        // Close the connection
        OutputStreamClient.close();
      } catch (IOException e) {
        System.err.println(e);
      } finally {
        try {
          if (Socket_Server != null)
            Socket_Server.close();
          if (Socket_Client != null)
            Socket_Client.close();
        } catch (IOException e) {
        }
      }
    }
  }
}

Starting proxy for Our Proxy Server:1025 on port 1026