June 2001
Intermediate to advanced
888 pages
21h 1m
English
Content preview from Java CookbookBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Reading the Contents of a URL
Problem
You want to read the contents of a URL (which can include a CGI, servlet, etc.).
Solution
Use the URL’s openConnection( )
or getContent( )
method. This is not dependent upon being in an applet.
Discussion
The URL class has several methods that allow you
to read. The first and simplest, openStream( )
, returns an
InputStream that can read the contents directly.
The simple
TextBrowser
program shown here calls
openStream( ) and uses this to construct a
BufferedReader to read text lines from what is
presumed to be a web server. I also demonstrate it reading a local
file to show that almost any valid URL can be used:
$ java TextBrowser http://localhost/ *** Loading http://localhost/... *** <HTML> <HEAD> <TITLE>Ian Darwin's Webserver On The Road</TITLE> <LINK REL="stylesheet" TYPE="text/css" HREF="/stylesheet.css" TITLE="Style"> </HEAD> <BODY BGCOLOR="#c0d0e0"> <H1>Ian Darwin's Webserver On The Road</H1> ... (rest of body omitted) ... $ java TextBrowser file:///etc/group *** Loading file:///etc/group... *** wheel:*:0:root daemon:*:1:daemon
The next method, openConnection( ), returns a
URLConnection object. This allows you more
flexibility, providing methods such as getHeaderField( ), getLastModified( ), and other
detailed methods. The third URL method, getContent( ), is more general. It returns an object that might be an
InputStream, or an object containing the data. Use
instanceof to determine which of several types was
returned.
See Also
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.