使用Java套接字类连接到Web服务器

Question

I am trying to create a simple web proxy app using Java(without using the HTTPUrlConnection class).

I have so far managed to successfully have my server listen on port 10000, and then accept a client connection when I enter a URL into my browser.

I now require my proxy to forward the HTTP request from the browser to the actual web server(the URL which I typed into the browser).

However, I am getting a java.net.UnknownHostException: when attempting to create a socket connection between my proxy and the web server. Does anyone know what may be causing this issue?

Below is the output showing the error aswell as the complete code aswell. Any help is very much appreciated!

Starting the socket server at port:10000
Listening.....
Socket[addr=/127.0.0.1,port=64099,localport=10000]has connected
URL IS http://www.hotmail.com
Can't connect
java.net.UnknownHostException: http://www.hotmail.com

---

import java.net.*;
import java.io.*;

public class Proxy {

private ServerSocket serverSocket;
private int port;

public Proxy(int port) {
    this.port = port; }

 public static void main(String[] args) {
    int port = 10000;             
    try {
        // initialize the proxy
        Proxy proxy = new Proxy(port);
        proxy.start();   
        } 
    catch (IOException e) {
        e.printStackTrace();
        }
}

public void start() throws IOException {
    System.out.println("Starting the socket server at port:" + port);
    serverSocket = new ServerSocket(port);

    //Listen for client connection
    System.out.println("Listening.....");
    Socket client = serverSocket.accept();

    //A client has connected to this server
    verifyClient(client);
}

private void verifyClient(Socket client) throws IOException {   
    System.out.println(client + "has connected");
    BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));

    //Parse the HTTP request from the browser and find the URL
    String request;
    while ((request = in.readLine()) != null) {
        if (request.contains("http://")){
            StringBuilder sb = new StringBuilder(request);
            sb.delete(0,4);
            sb.delete(sb.length()-9,sb.length());
            makeConnection(sb.toString());              
            break;}
        in.close();
    }   
}

private void makeConnection(String url) throws IOException{
//Establish connection between proxy & web server on socket
try {
    InetAddress addr;
    URL aURL = new URL(url);
    System.out.println("URL IS " + aURL.toString());
    Socket server = new Socket(urlString,80);
    addr = server.getInetAddress();
    System.out.println("IP is: " + addr);
    System.out.println("Connected to " + addr);
    server.close();
}
catch (IOException e) {
    System.out.println("Can't connect");
    System.out.println(e);
    }

}

Answer 1

From your update, it seems like you are trying to create a socket connection to " http://www.hotmail.com ". This should just be www.hotmail.com. The "http://" before this is a problem.