Jakarta Commons Cookbook

11.6. Debugging HTTP Communications

Problem

You need to see the low-level communications between the client and the server.

Solution

Set four System variables that control logging, and HttpClient will produce debugging statements dealing with environment information, SSL configuration information, and the raw data sent to and received from the server. The following example sets the four System properties that control HttpClient debugging output:

               import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.methods.GetMethod;

String logging = "org.apache.commons.logging";

// Configure Logging
System.setProperty(logging + ".Log", logging + ".impl.SimpleLog");
System.setProperty(logging + ".logging.simplelog.showdatetime", "true");
System.setProperty(logging + ".simplelog.log.httpclient.wire", "debug");        
System.setProperty(logging + ".simplelog.log.org.apache.commons.httpclient", 
                   "debug");
        
HttpClient client = new HttpClient( );
String url = "http://www.discursive.com/jccook/";
HttpMethod method = new GetMethod( url );
client.executeMethod( method );
String response = method.getResponseBodyAsString( );

System.out.println( response );
method.releaseConnection( );
method.recycle( );

This code executes a simple GetMethod and produces the following debugging output, which contains environment information and a log of all data sent and received from the server:

HttpClient ...