Presents your  
JAVA E-NEWSLETTER for December 18, 2003 
 
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BUILDING WEB CLIENTS WITH HTTP CLIENT   

The next time you're building a Web-aware application and the Java API 
isn't enough, you may want to check out Jakarta Commons' HTTP Client. 
Using HTTP Client is straightforward: Create an instance of HttpClient, 
create an instance of the method type you want to use, and then execute
the 
method using the instance of HttpClient.   
  
Below is an example of fetching a Web page and dumping its content to 
standard out.   
  
    HttpClient client = new HttpClient();   
    GetMethod get = new GetMethod(" http://www.google.com/");   
  
    client.executeMethod(get);   
    System.out.println(get.getResponseBodyAsString());   
  
Now suppose that you need to use the basic authentication mechanism to 
access a page. In this case, you need to use the HTTP Client class 
UsernamePasswordCredentials. Here's the code to add to accomplish this: 
 
  
    UsernamePasswordCredentials upc =   
            new UsernamePasswordCredentials("foo", "bar");   
  
    client.getState().setCredentials(null, null, upc);   
  
    get.setDoAuthentication(true);   
  
In the following code, we add a timeout specification to the get method 
in case the page takes a long time to load.   
  
    client.setConnectionTimeout(60000);   
       
  
As the sample code illustrates, making use of the features in HTTP 
Client is simple. If your application needs HTTP access, then check out
HTTP 
Client. It has more features than the Web-aware classes in the Java 
API,

and it's easy to use. Take a look for yourself and see if it suits your 
needs.   
  
import java.io.IOException;   
import org.apache.commons.httpclient.HttpClient;   
import org.apache.commons.httpclient.UsernamePasswordCredentials;   
import org.apache.commons.httpclient.methods.GetMethod;   
  
public class HttpClientTip {   
    public static void main(String args[]) {   
        try {   
            HttpClient client = new HttpClient();   
            GetMethod get = new GetMethod(" http://www.google.com/");   
  
            UsernamePasswordCredentials upc =   
                    new UsernamePasswordCredentials("foo", "bar");   
  
            client.getState().setCredentials(null, null, upc);   
  
            get.setDoAuthentication(true);   
  
            client.setConnectionTimeout(60000);   
  
            client.executeMethod(get);   
            System.out.println(get.getResponseBodyAsString());   
        }   
        catch (IOException e) {   
            e.printStackTrace();   
        }   
    }   
}   
  
Find out more about HTTP Client's many features, including HTTPS, 
multipart POSTs, and proxy support, by visiting The Jakarta Project
site.   
http://jakarta.apache.org/commons/httpclient/   
  
David Petersheim is the Director of Application Development with 
Genscape, Inc. He designs and develops server-side applications to
acquire and 
process real-time energy data.   
  
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