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This module shows how to use the URLConnection class.

Table of contents


This module is one in a collection of modules designed for teaching INEW 2338 Advanced Java (Web) at Austin Community College in Austin, TX. More specifically, it is one in asub-collection of modules designed for teaching network programming in that course. The purpose of this module is to introduce the student to the URLConnection class.

Viewing tip

I recommend that you open another copy of this module in a separate browser window and use the following links to easily find and view the Figuresand Listings while you are reading about them.



General background information

I don't plan to say very much about the URLConnection class. It is an abstract class that can be extended , and it has a protected constructor that takes a URL object as a parameter.

It has variables or fields that contain useful information about a connection.

It has many methods that can be used to examine and manipulate an object of the class in a variety of different ways.

If you plan to use the URL class for the higher-lever capabilities that it offers, and you plan to write content handlers and protocol handlers , you will probably need to become very familiar with this class. In that case, you will probably want to get a copy of a good Java networkingbook, such as Java Network Programming , by Elliotte Rusty Howard, and study the use of this class in depth.

My objective here is simply to make you aware of the existence of the class and its many methods, and to provide some examples of how you can get and use anobject of the class to obtain higher-level information about a connection.

Discussion and sample code

This program illustrates connecting to a URL and creating a URLConnection object.

The program uses the URLConnection object to obtain and display some of the "higher level" information about the UR L:

  • the URL
  • the date last modified
  • the content type

The computer must be online for this program to run properly. Otherwise, it will throw an exception of type UnknownHostException .

Partial program output

Figure 1 shows part of the output from the program. The first three lines of output correspond to the items in the above list , and are the items that we will be primarily interested in for this module.

Figure 1 - Partial program output.
http://www.austincc.edu/baldwin/page1.html Tue Apr 17 23:16:17 CDT 2001text/html; charset=iso-8859-1<!doctype html public "-//w3c//dtd html 4.0 transitional//en"><html><head><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><meta name="GENERATOR" content="Mozilla/4.7 [en] (WinNT; I) [Netscape]"><title>Java and JavaScript Programming, by Richard G Baldwin</title></head><body bgcolor="#FFFFFF" link="#0000FF" vlink="#FF0000" lang="EN-US"><h1>Baldwin's Test Page 1</h1>Click<a href="http://www2.austin.cc.tx.us/baldwin/page2.html">here</a>to view page 2<p>Note: The material on this page is not intended to be of any particular value. This file is posted for the purpose of testing HTTP networkprograms only.<p>The following red bar is a centered gif file.<center><p><img SRC="red_thick_line_1.gif" BORDER=0 id="_x0000_i1025" height=9 width=300></center>

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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