proxy.txt

编写简单的代理服务器.rar

基本原理： 
  代理服务器打开一个端口接收浏览器发来的访问某个站点的请求，从请求的字符串中解析出用户想访问哪个网页，让后通过URL对象建立输入流读取相应的网页内容，最后按照web服务器的工作方式将网页内容发送给用户浏览器 
源程序： 
import java.net.*; 
import java.io.*; 
public class MyProxyServer 
{ 
public static void main(String args[]) 
{ 
try 
{ 
ServerSocket ss=new ServerSocket(8080); 
System.out.println("proxy server OK"); 
while (true) 
{ 
Socket s=ss.accept(); 
process p=new process(s); 
Thread t=new Thread(p); 
t.start(); 
} 
} 
catch (Exception e) 
{ 
System.out.println(e); 
} 
} 
}; 
class process implements Runnable 
{ 
Socket s; 
public process(Socket s1) 
{ 
s=s1; 
} 
public void run() 
{ 
String content=" "; 
try 
{ 
PrintStream out=new PrintStream(s.getOutputStream()); 
BufferedReader in=new BufferedReader(new InputStreamReader(s.getInputStream())); 
String info=in.readLine(); 
System.out.println("now got "+info); 
int sp1=info.indexOf(' '); 
int sp2=info.indexOf(' ',sp1+1); 
String gotourl=info.substring(sp1,sp2); 
System.out.println("now connecting "+gotourl); 
URL con=new URL(gotourl); 
InputStream gotoin=con.openStream(); 
int n=gotoin.available(); 
byte buf[]=new byte[1024]; 
out.println("HTTP/1.0 200 OK"); 
out.println("MIME_version:1.0"); 
out.println("Content_Type:text/html"); 
out.println("Content_Length:"+n); 
out.println(" "); 
while ((n=gotoin.read(buf))>=0) 
{ 
out.write(buf,0,n); 
} 
out.close(); 
s.close(); 
} 
catch (IOException e) 
{ 
System.out.println("Exception:"+e); 
} 
} 
};