Java 创建带有套接字的简单代理服务器示例

在这些示例中，您可以找到创建简单代理套接字服务器的不同方法。由于多种原因，这对您很有用：

捕获客户端和服务器之间的流量。
限制上传/下载带宽，以了解您的网站是如何加载慢速连接的。
查看网络出现问题时系统的反应。
"动态"修改客户端/服务器的内容（发送的接收）。
生成有关流量的统计信息。

*您可以使用此处的示例作为开发的基础。尚未实现任何功能。以下示例只是代理。您不能总是将它们用作 HTTP 代理。

示例 1（多插槽代理服务器）

使用示例 1 作为另一个 HTTP 代理的 HTTP 代理

示例 2（同时只有 1 个插槽）

示例 3 HTTP 代理

示例 1

import java.io.*;
import java.net.*;/**** @author jcgonzalez.com**/
public class ProxyMultiThread {public static void main(String[] args) {try {if (args.length != 3)throw new IllegalArgumentException("insuficient arguments");// and the local port that we listen for connections onString host = args[0];int remoteport = Integer.parseInt(args[1]);int localport = Integer.parseInt(args[2]);// Print a start-up messageSystem.out.println("Starting proxy for " + host + ":" + remoteport + " on port " + localport);ServerSocket server = new ServerSocket(localport);while (true) {new ThreadProxy(server.accept(), host, remoteport);}} catch (Exception e) {System.err.println(e);System.err.println("Usage: java ProxyMultiThread " + "<host> <remoteport> <localport>");}}
}/*** Handles a socket connection to the proxy server from the client and uses 2* threads to proxy between server and client** @author jcgonzalez.com**/
class ThreadProxy extends Thread {private Socket sClient;private final String SERVER_URL;private final int SERVER_PORT;ThreadProxy(Socket sClient, String ServerUrl, int ServerPort) {this.SERVER_URL = ServerUrl;this.SERVER_PORT = ServerPort;this.sClient = sClient;this.start();}@Overridepublic void run() {try {final byte[] request = new byte[1024];byte[] reply = new byte[4096];final InputStream inFromClient = sClient.getInputStream();final OutputStream outToClient = sClient.getOutputStream();Socket client = null, server = null;// connects a socket to the servertry {server = new Socket(SERVER_URL, SERVER_PORT);} catch (IOException e) {PrintWriter out = new PrintWriter(new OutputStreamWriter(outToClient));out.flush();throw new RuntimeException(e);}// a new thread to manage streams from server to client (DOWNLOAD)final InputStream inFromServer = server.getInputStream();final OutputStream outToServer = server.getOutputStream();// a new thread for uploading to the servernew Thread() {public void run() {int bytes_read;try {while ((bytes_read = inFromClient.read(request)) != -1) {outToServer.write(request, 0, bytes_read);outToServer.flush();// TODO CREATE YOUR LOGIC HERE}} catch (IOException e) {}try {outToServer.close();} catch (IOException e) {e.printStackTrace();}}}.start();// current thread manages streams from server to client (DOWNLOAD)int bytes_read;try {while ((bytes_read = inFromServer.read(reply)) != -1) {outToClient.write(reply, 0, bytes_read);outToClient.flush();// TODO CREATE YOUR LOGIC HERE}} catch (IOException e) {e.printStackTrace();} finally {try {if (server != null)server.close();if (client != null)client.close();} catch (IOException e) {e.printStackTrace();}}outToClient.close();sClient.close();} catch (IOException e) {e.printStackTrace();}}
}

编译和使用

javac ProxyMultiThread.java

java ProxyMultiThread 192.168.1.10 8080 9999

在端口 9999 上启动 192.168.1.10：8180 的代理

（现在流量通过代理从localhost 9999重定向到192.168.1.10。请记住，由于HTTP主机标签，引用程序，javascript重定向等原因，Web浏览器可能并不总是有效。

使用示例 1 作为另一个 HTTP 代理的 HTTP 代理

如果您的 HTTP 代理在端口380上myproxy.test.net，并且您希望在 java 到达代理之前使用 java 作为代理，则应按如下方式运行它。

java ProxyMultiThread myproxy.test.net 80 9999

现在调整浏览器配置以使用本地主机 9999 上的代理

在火狐浏览器中：

*现在，您的所有流量都应该先转到示例1，然后再转到您的代理。

示例 2


// This example is from _Java Examples in a Nutshell_. (http://www.oreilly.com)
// Copyright (c) 1997 by David Flanagan
// This example is provided WITHOUT ANY WARRANTY either expressed or implied.
// You may study, use, modify, and distribute it for non-commercial purposes.
// For any commercial use, see http://www.davidflanagan.com/javaexamples
import java.io.*;
import java.net.*;/*** This class implements a simple single-threaded proxy server.**/
public class SimpleProxyServer {/** The main method parses arguments and passes them to runServer */public static void main(String[] args) throws IOException {try {// Check the number of argumentsif (args.length != 3)throw new IllegalArgumentException("Wrong number of arguments.");// Get the command-line arguments: the host and port we are proxy for// and the local port that we listen for connections onString host = args[0];int remoteport = Integer.parseInt(args[1]);int localport = Integer.parseInt(args[2]);// Print a start-up messageSystem.out.println("Starting proxy for " + host + ":" + remoteport + " on port " + localport);// And start running the serverrunServer(host, remoteport, localport); // never returns} catch (Exception e) {System.err.println(e);System.err.println("Usage: java SimpleProxyServer " + "<host> <remoteport> <localport>");}}/*** This method runs a single-threaded proxy server for host:remoteport on the* specified local port. It never returns.**/public static void runServer(String host, int remoteport, int localport) throws IOException {// Create a ServerSocket to listen for connections withServerSocket ss = new ServerSocket(localport);// Create buffers for client-to-server and server-to-client communication.// We make one final so it can be used in an anonymous class below.// Note the assumptions about the volume of traffic in each direction...final byte[] request = new byte[1024];byte[] reply = new byte[4096];// This is a server that never returns, so enter an infinite loop.while (true) {// Variables to hold the sockets to the client and to the server.Socket client = null, server = null;try {// Wait for a connection on the local portclient = ss.accept();// Get client streams. Make them final so they can// be used in the anonymous thread below.final InputStream from_client = client.getInputStream();final OutputStream to_client = client.getOutputStream();// Make a connection to the real server// If we cannot connect to the server, send an error to the// client, disconnect, then continue waiting for another connection.try {server = new Socket(host, remoteport);} catch (IOException e) {PrintWriter out = new PrintWriter(new OutputStreamWriter(to_client));out.println("Proxy server cannot connect to " + host + ":" + remoteport + ":\n" + e);out.flush();client.close();continue;}// Get server streams.final InputStream from_server = server.getInputStream();final OutputStream to_server = server.getOutputStream();// Make a thread to read the client's requests and pass them to the// server. We have to use a separate thread because requests and// responses may be asynchronous.new Thread() {public void run() {int bytes_read;try {while ((bytes_read = from_client.read(request)) != -1) {to_server.write(request, 0, bytes_read);System.out.println(bytes_read + "to_server--->" + new String(request, "UTF-8") + "<---");to_server.flush();}} catch (IOException e) {}// the client closed the connection to us, so close our// connection to the server. This will also cause the// server-to-client loop in the main thread exit.try {to_server.close();} catch (IOException e) {}}}.start();// Meanwhile, in the main thread, read the server's responses// and pass them back to the client. This will be done in// parallel with the client-to-server request thread above.int bytes_read;try {while ((bytes_read = from_server.read(reply)) != -1) {try {Thread.sleep(1);System.out.println(bytes_read + "to_client--->" + new String(request, "UTF-8") + "<---");} catch (InterruptedException e) {e.printStackTrace();}to_client.write(reply, 0, bytes_read);to_client.flush();}} catch (IOException e) {}// The server closed its connection to us, so close our// connection to our client. This will make the other thread exit.to_client.close();} catch (IOException e) {System.err.println(e);}// Close the sockets no matter what happens each time through the loop.finally {try {if (server != null)server.close();if (client != null)client.close();} catch (IOException e) {}}} // while(true)}
}

示例 3 HTTP 代理

我使用Benjamin Kohl&Artem Melnik的HTTP Java Proxy下载这里或转到原始网站这里.

笔记

您可以使用Thread.sleep来限制带宽，抛出随机异常以扰乱网络，修改内容等。