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 Tools and Libs > Commons Http Client > Basic Preemptive Authentication

Basic Preemptive Authentication 

Commons Http Client is a HTTP agent implementation in java supporting client-side authentication, HTTP state management and HTTP connection management. This requires the libraries httpclient-4.1.2.jar, httpcore-4.1.2.jar, httpmime-4.1.2.jar, httpclient-cache-4.1.2.jar, commons-codec.jar and commons-logging-1.1.1.jar to be in classpath. The following example shows how to access a JSP page protected through basic authentication in Tomcat v6.0.

Configure a new tomcat user venakat and role btc in tomcat-users.xml as shown below,

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Configure BASIC Authentication for HTTP_TEST_APP in web.xml as shown below,

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A simple JSP page protected through BASIC Authentication.

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A simple Http Client to access the protected JSP. We can see that the basic authentiction information is passed as request header in the format Authorization : Basic Base64(username:password)

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Author  :  Sudhakar KV
Email  :  [email protected]
package com.bethecoder.tutorials.commons_httpclient;


import org.apache.http.auth.AuthScope;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.BasicResponseHandler;
import org.apache.http.impl.client.DefaultHttpClient;

public class BasicPreemptiveAuthenticationTest {

   @param args
   @throws IOException 
   @throws ClientProtocolException 
  public static void main(String[] argsthrows ClientProtocolException, IOException {
    DefaultHttpClient httpclient = new DefaultHttpClient();
    HttpGet httpget = new HttpGet("http://localhost:8080/HTTP_TEST_APP/basic_protected.jsp");
    System.out.println("Requesting : " + httpget.getURI());

    try {
      UsernamePasswordCredentials credentials = new UsernamePasswordCredentials("venkat""mypassword");
      AuthScope authscope = new AuthScope("localhost"8080, AuthScope.ANY_REALM);
      httpclient.getCredentialsProvider().setCredentials(authscope, credentials);

      ResponseHandler<String> responseHandler = new BasicResponseHandler();
            String responseBody = httpclient.execute(httpget, responseHandler);
      System.out.println("responseBody : " + responseBody);
    finally {



It gives the following output,
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