直接貼程式碼，不解釋

1 主服務，用來偵聽埠

package org.javaren.proxy;

import java.net.ServerSocket;
import java.net.Socket;

public class SocketProxy {
	/**
	 * @param args
	 */
	public static void main(String[] args) throws Exception {
		ServerSocket serverSocket = new ServerSocket(8888);
		while (true) {
			Socket socket = null;
			try {
				socket = serverSocket.accept();
				new SocketThread(socket).start();
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
	}
}
 

內部設計了Socket的認證，自己看吧

package org.javaren.proxy;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;

public class SocketThread extends Thread {
	private Socket socketIn;
	private InputStream isIn;
	private OutputStream osIn;
	//
	private Socket socketOut;
	private InputStream isOut;
	private OutputStream osOut;

	public SocketThread(Socket socket) {
		this.socketIn = socket;
	}

	private byte[] buffer = new byte[4096];
	private static final byte[] VER = { 0x5, 0x0 };
	private static final byte[] CONNECT_OK = { 0x5, 0x0, 0x0, 0x1, 0, 0, 0, 0, 0, 0 };

	public void run() {
		try {
			System.out.println("\n\na client connect " + socketIn.getInetAddress() + ":" + socketIn.getPort());
			isIn = socketIn.getInputStream();
			osIn = socketIn.getOutputStream();
			int len = isIn.read(buffer);
			System.out.println("< " + bytesToHexString(buffer, 0, len));
			osIn.write(VER);
			osIn.flush();
			System.out.println("> " + bytesToHexString(VER, 0, VER.length));
			len = isIn.read(buffer);
			System.out.println("< " + bytesToHexString(buffer, 0, len));
			// 查詢主機和埠
			String host = findHost(buffer, 4, 7);
			int port = findPort(buffer, 8, 9);
			System.out.println("host=" + host + ",port=" + port);
			socketOut = new Socket(host, port);
			isOut = socketOut.getInputStream();
			osOut = socketOut.getOutputStream();
			//
			for (int i = 4; i <= 9; i++) {
				CONNECT_OK[i] = buffer[i];
			}
			osIn.write(CONNECT_OK);
			osIn.flush();
			System.out.println("> " + bytesToHexString(CONNECT_OK, 0, CONNECT_OK.length));
			SocketThreadOutput out = new SocketThreadOutput(isIn, osOut);
			out.start();
			SocketThreadInput in = new SocketThreadInput(isOut, osIn);
			in.start();
			out.join();
			in.join();
		} catch (Exception e) {
			System.out.println("a client leave");
		} finally {
			try {
				if (socketIn != null) {
					socketIn.close();
				}
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		System.out.println("socket close");
	}

	public static String findHost(byte[] bArray, int begin, int end) {
		StringBuffer sb = new StringBuffer();
		for (int i = begin; i <= end; i++) {
			sb.append(Integer.toString(0xFF & bArray[i]));
			sb.append(".");
		}
		sb.deleteCharAt(sb.length() - 1);
		return sb.toString();
	}

	public static int findPort(byte[] bArray, int begin, int end) {
		int port = 0;
		for (int i = begin; i <= end; i++) {
			port <<= 16;
			port += bArray[i];
		}
		return port;
	}

	// 4A 7D EB 69
	// 74 125 235 105
	public static final String bytesToHexString(byte[] bArray, int begin, int end) {
		StringBuffer sb = new StringBuffer(bArray.length);
		String sTemp;
		for (int i = begin; i < end; i++) {
			sTemp = Integer.toHexString(0xFF & bArray[i]);
			if (sTemp.length() < 2)
				sb.append(0);
			sb.append(sTemp.toUpperCase());
			sb.append(" ");
		}
		return sb.toString();
	}
}
 

3  讀取執行緒，負責外面讀資料，寫入到請求端

package org.javaren.proxy;

/**
 * * 從外部讀取，向內部發送資訊
 */
import java.io.InputStream;
import java.io.OutputStream;

public class SocketThreadInput extends Thread {
	private InputStream isOut;
	private OutputStream osIn;

	public SocketThreadInput(InputStream isOut, OutputStream osIn) {
		this.isOut = isOut;
		this.osIn = osIn;
	}

	private byte[] buffer = new byte[409600];

	public void run() {
		try {
			int len;
			while ((len = isOut.read(buffer)) != -1) {
				if (len > 0) {
					System.out.println(new String(buffer, 0, len));
					osIn.write(buffer, 0, len);
					osIn.flush();
				}
			}
		} catch (Exception e) {
			System.out.println("SocketThreadInput leave");
		}
	}
}
 

package org.javaren.proxy;

import java.io.InputStream;
import java.io.OutputStream;

/**
 * 從內部讀取，向外部發送資訊
 * 
 * @author zxq
 * 
 */
public class SocketThreadOutput extends Thread {
	private InputStream isIn;
	private OutputStream osOut;

	public SocketThreadOutput(InputStream isIn, OutputStream osOut) {
		this.isIn = isIn;
		this.osOut = osOut;
	}

	private byte[] buffer = new byte[409600];

	public void run() {
		try {
			int len;
			while ((len = isIn.read(buffer)) != -1) {
				if (len > 0) {
					System.out.println(new String(buffer, 0, len));
					osOut.write(buffer, 0, len);
					osOut.flush();
				}
			}
		} catch (Exception e) {
			System.out.println("SocketThreadOutput leave");
		}
	}
}

效果還不錯，用firefox/ ie都測試過，可用。