Problem of reading source HTML document via URL object?

Question

Hi, Friends,
why the following simple program can't work correctly?
import java.net.*;
import java.io.*;
public class URLReader {
public static void main(String[] args) throws Exception {
     URL ieee = new URL("http://www.ieee.com/");
     BufferedReader in = new BufferedReader(
                    new InputStreamReader(
                    yahoo.openStream()));
     String inputLine;
     while ((inputLine = in.readLine()) != null)
     System.out.println(inputLine);
     in.close();
you know, when we use http://www.ieee.com/ to visit the ieee website via browser, it works well, only the adress is reset to http://ieee.com/portal/site/iportals/ , why the browser can do that, while the URL object can't?

Answer 1

A URL is simply a reference to a "file" location.
To do I/O on that object requires some sort of protocol. HTTP (a "web server"), will allow you to do this, but uses the HttpURLConnection object.
The Java Tutorials shows you CAN read/write to a URL, but requires the underlying HTTP protocol client implementation.
I think you are using this code from the Sun site: http://java.sun.com/docs/books/tutorial/networking/urls/readingURL.html
Which may be why you create 'ieee' but reference 'yahoo' in your code.
Were you getting an error message when trying to compile your program?
You may wish to look further into the tutorial pages at: http://java.sun.com/docs/books/tutorial/networking/urls/readingWriting.html
But I still would refer you in the end to HttpURLConnection which is much more in-depth.