java实现http代理服务

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package httpProxy;/************************************* * 一个基础的代理服务器类 ************************************* */import java.net.*;import java.io.*;public class HttpProxy extends Thread {static public int CONNECT_RETRIES = 5;static public int CONNECT_PAUSE = 5;static public int TIMEOUT = 50;static public int BUFSIZ = 1024;static public boolean logging = false;static public OutputStream log = null;// 传入数据用的Socketstatic public Socket socket;// 上级代理服务器，可选static private String parent = null;static private int parentPort = -1;static public void setParentProxy(String name, int pport) {parent = name;parentPort = pport;}// 在给定Socket上创建一个代理线程。public HttpProxy(Socket s) {socket = s;start();}public void writeLog(int c, boolean browser) throws IOException {log.write(c);}public void writeLog(byte[] bytes, int offset, int len, boolean browser)throws IOException {for (int i = 0; i < len; i++)writeLog((int) bytes[offset + i], browser);}// 默认情况下，日志信息输出到// 标准输出设备// 派生类可以覆盖它public String processHostName(String url, String host, int port, Socket sock) {java.text.DateFormat cal = java.text.DateFormat.getDateTimeInstance();System.out.println(cal.format(new java.util.Date()) + " - " + url + " "+ sock.getInetAddress() + "\n");return host;}// 执行操作的线程public void run() {String line;String host;int port = 80;Socket outbound = null;try {socket.setSoTimeout(TIMEOUT);InputStream is = socket.getInputStream();OutputStream os = null;try {// 获取请求行的内容line = "";host = "";int state = 0;boolean space;while (true) {int c = is.read();if (c == -1)break;if (logging)writeLog(c, true);space = Character.isWhitespace((char) c);switch (state) {case 0:if (space)continue;state = 1;case 1:if (space) {state = 2;continue;}line = line + (char) c;break;case 2:if (space)continue; // 跳过多个空白字符state = 3;case 3:if (space) {state = 4;// 只取出主机名称部分String host0 = host;int n;n = host.indexOf("//");if (n != -1)host = host.substring(n + 2);n = host.indexOf('/');if (n != -1)host = host.substring(0, n);// 分析可能存在的端口号n = host.indexOf(":");if (n != -1) {port = Integer.parseInt(host.substring(n + 1));host = host.substring(0, n);}host = processHostName(host0, host, port, socket);if (parent != null) {host = parent;port = parentPort;}int retry = CONNECT_RETRIES;while (retry-- != 0) {try {outbound = new Socket(host, port);break;} catch (Exception e) {}// 等待Thread.sleep(CONNECT_PAUSE);}if (outbound == null)break;outbound.setSoTimeout(TIMEOUT);os = outbound.getOutputStream();os.write(line.getBytes());os.write(' ');os.write(host0.getBytes());os.write(' ');pipe(is, outbound.getInputStream(), os,socket.getOutputStream());break;}host = host + (char) c;break;}}} catch (IOException e) {}} catch (Exception e) {} finally {try {socket.close();} catch (Exception e1) {}try {outbound.close();} catch (Exception e2) {}}}void pipe(InputStream is0, InputStream is1, OutputStream os0,OutputStream os1) throws IOException {try {int ir;byte bytes[] = new byte[BUFSIZ];while (true) {try {if ((ir = is0.read(bytes)) > 0) {os0.write(bytes, 0, ir);if (logging)writeLog(bytes, 0, ir, true);} else if (ir < 0)break;} catch (InterruptedIOException e) {}try {if ((ir = is1.read(bytes)) > 0) {os1.write(bytes, 0, ir);if (logging)writeLog(bytes, 0, ir, false);} else if (ir < 0)break;} catch (InterruptedIOException e) {}}} catch (Exception e0) {System.out.println("Pipe异常: " + e0);}}static public void startProxy(int port, Class clobj) {ServerSocket ssock;try {ssock = new ServerSocket(port);while (true) {Class[] sarg = new Class[1];Object[] arg = new Object[1];sarg[0] = Socket.class;try {java.lang.reflect.Constructor cons = clobj.getDeclaredConstructor(sarg);arg[0] = ssock.accept();cons.newInstance(arg); // 创建HttpProxy或其派生类的实例} catch (Exception e) {Socket esock = (Socket) arg[0];try {esock.close();} catch (Exception ec) {}}}} catch (IOException e) {}}static public void stopProxy(){try {if(null!=HttpProxy.socket)HttpProxy.socket.close(); } catch (IOException e) { e.printStackTrace();}}// 测试用的简单main方法static public void main(String args[]) {System.out.println("在端口808启动代理服务器\n");HttpProxy.log = System.out;HttpProxy.logging = false;HttpProxy.startProxy(808, HttpProxy.class);}}