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Socket            static 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);            }        }