你需要做这样的事情

import java.io.*;

import java.net.URL;

import java.net.URLConnection;

import javax.servlet.http.*;

import javax.servlet.*;

public class URLServlet extends HttpServlet {

public void doGet(HttpServletRequest req, HttpServletResponse res)

throws ServletException, IOException {

URL urldemo = new URL("http://www.demo.com/");

URLConnection yc = urldemo.openConnection();

BufferedReader in = new BufferedReader(new InputStreamReader(

yc.getInputStream()));

String inputLine;

while ((inputLine = in.readLine()) != null)

System.out.println(inputLine);

in.close();

}

}

普通的java程序

import java.io.BufferedReader;

import java.io.InputStreamReader;

import java.net.URL;

import java.net.URLConnection;

public class URLServlet {

public static void main(String s[]) {

try {

URL urldemo = new URL("http://www.google.com/");

URLConnection yc = urldemo.openConnection();

BufferedReader in = new BufferedReader(new InputStreamReader(

yc.getInputStream()));

String inputLine;

while ((inputLine = in.readLine()) != null)

System.out.println(inputLine);

in.close();

}catch(Exception e) {

System.out.println(e);

}

}

}