eXtropia: the open web technology company
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 ::   Tutorials
 ::   Presentations
Perl & CGI tutorials
 ::   Intro to Perl/CGI and HTML Forms
 ::   Intro to Windows Perl
 ::   Intro to Perl 5
 ::   Intro to Perl
 ::   Intro to Perl Taint mode
 ::   Sherlock Holmes and the Case of the Broken CGI Script
 ::   Writing COM Components in Perl

Java tutorials
 ::   Intro to Java
 ::   Cross Browser Java

Misc technical tutorials
 ::   Intro to The Web Application Development Environment
 ::   Introduction to XML
 ::   Intro to Web Design
 ::   Intro to Web Security
 ::   Databases for Web Developers
 ::   UNIX for Web Developers
 ::   Intro to Adobe Photoshop
 ::   Web Programming 101
 ::   Introduction to Microsoft DNA

Misc non-technical tutorials
 ::   Misc Technopreneurship Docs
 ::   What is a Webmaster?
 ::   What is the open source business model?
 ::   Technical writing
 ::   Small and mid-sized businesses on the Web

Offsite tutorials
 ::   ISAPI Perl Primer
 ::   Serving up web server basics
 ::   Introduction to Java (Parts 1 and 2) in Slovak


Introduction to Web Programming
Connecting to a Server  
  • Connecting to a server is extremely easy with Java's built in socket classes for communicating via HTTP. You will recall from day two how we connected to a web server using the GET and POST methods of HTTP. Well in java, the process is exactly the same Specifically, you create a socket object which connects to a server somewhere on the web using syntax such as the following:

    Socket s = new Socket("url", portNumber);

  • Thus, the following code would open a socket to www.extropia.com on port 80:

    Socket s = new Socket("www.extropia.com", 80);

  • So what happens if your application cannot reach the server specified? Well, it is essential that you place your networking within a try block which catches several errors such as UnknownHostException, MalformedURLException, and IOException.

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