import java.net.*;

import java.io.*;

public class HttpProxy extends Thread {

//设定重试的次数

static public int CONNECT_RETRIES=5;

//5停止的时间

static public int CONNECT_PAUSE=5;

static public int TIMEOUT=50;

static public int BUFSIZ=1024;//缓冲区大小

static public boolean logging = false;

static public OutputStream log=null;//输出流

// 传入数据用的Socket

protected Socket socket;

// 上级代理服务器，可选

static private String parent=null;

static private int parentPort=-1;

//设定代理服务器

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();

}

//记录信息

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())+ " \n "+url+"\n "+

sock.getInetAddress()+"\n");

return host;

}

// 执行操作的线程

public void run() {

String line;

String host;

int port=80;//设定端口号

Socket outbound=null;

try {

//设定停止时间

socket.setSoTimeout(TIMEOUT);

//获得输入流

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;//跳出循环

if (logging) writeLog(c,true);

space=Character.isWhitespace((char)c);

//通过不同状态选择处理过程

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 {

//重新获得套接字

outbound=new Socket(host,port);

break;

} catch (Exception e) { }

// 等待

Thread.sleep(CONNECT_PAUSE);

}

if (outbound==null) break;

//设定停顿时间

outbound.setSoTimeout(TIMEOUT);

os=outbound.getOutputStream();

//通过写缓冲的方式

os.write(line.getBytes());

os.write(' ');//发送标记符

os.write(host0.getBytes());

os.write(' ');

pipe(is,outbound.getInputStream(),

os,socket.getOutputStream());

break;//跳出循环

}

host=host+(char)c;

break;//跳出循环

}

}

}

catch (IOException e) { }

} catch (Exception e) { }

finally {

try { socket.close();} catch (Exception e1) {}//关闭套接字

try { outbound.close();} catch (Exception e2) {}

}

}

//通过管道的方式处理

void pipe(InputStream is0, InputStream is1,

OutputStream os0, OutputStream os1)

throws IOException {

try {

int ir;

byte bytes[]=new byte[BUFSIZ];//设定缓冲区

while (true) {

try {

if ((ir=is0.read(bytes))>0) {

os0.write(bytes,0,ir);//写缓冲的方式

if (logging) writeLog(bytes,0,ir,true);

}

else if (ir<0)

break;//跳出循环

} catch (InterruptedIOException e) { }

try {

if ((ir=is1.read(bytes))>0) {

os1.write(bytes,0,ir);//通过写缓冲

if (logging) writeLog(bytes,0,ir,false);

}

else if (ir<0)

break;//跳出循环

} catch (InterruptedIOException e) { }

}

} catch (Exception e0) {

System.out.println("Pipe异常: " + e0);

}

}

static public void startProxy(int port,Class clobj) {

ServerSocket ssock;//服务器套接字

//Socket sock;

try {

ssock=new ServerSocket(port);//实例化服务器套接字

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();

//创建HttpProxy或其派生类的实例

cons.newInstance(arg);

}

catch (Exception e) {

Socket esock = (Socket)arg[0];

try {

esock.close();

}

catch (Exception ec) {}//输出错误信息

}

}

} catch (IOException e) {

}

}

// 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;//记录信息

HttpProxy.logging=false;

HttpProxy.startProxy(808,HttpProxy.class);

}

}