Hello!
I am a newbie for servlet applications, trying to learn the subject. On my way, I wrote a servlet class called FormWebServlet that uses the org.apache.http.impl.client.DefaultHttpClient class. However, I get the exception
java.lang.ClassNotFoundException: org.apache.http.impl.client.DefaultHttpClient
... that clearly shows that this class does not exist, although I have added the jar file to the project.
The server returns an "HTTP Status 500" error with the message that the "root cause" is this missing class:
java.lang.NoClassDefFoundError: org/apache/http/impl/client/DefaultHttpClient
testPackage.FormWebServlet.doGet(FormWebServlet.java:45)
javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
TRIES
1) I searched for the missing jar file and added it to the project (by going on the project in "Eclipse JAVA EE IDE for Web Developers, 20100917-0705"'s project explorer, select "Properties", selected the "Java Build Path" and clicked the [Add External JARs...] button.) The added jar file is from the Apache site and is called httpclient-4.1.1.jar.
2) As I still get the same error, I extracted with 7-ZIP the DefaultHttpClient.class file and put it into the WebContent/WEB-INF/lib directory.
QUESTION
What am I doing wrong?
Notice: If I comment the definition of
HttpClient client = new DefaultHttpClient();
... and try to declare an HttpGet object instead with
final String ADDRESS = ServletUtilities.getHttpAddress(BAR_CODE);
out.println("ADDRESS = \"" + ADDRESS + '\"');
HttpGet get = new HttpGet(ADDRESS);
... I get the same error, but this time for the class HttpGet - both part of the same JAR file.
DETAILS
Inculded JARs:
common-httpclient-3.0.1.jar
httpclient-4.1.1.jar
httpcore-4.1.jar
FormWebServlet.jar:
/**
*
*/
package testPackage;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import coreServlets.ServletUtilities;
/**
*
*/
@WebServlet(description = "Gets the book's barcode with a form", urlPatterns = { "/FormWebServlet" })
public class FormWebServlet extends HttpServlet {
/** */
private static final long serialVersionUID = 6008315960327824633L;
/**
* @see HttpServlet#doGet(HttpServletRequest request,
* HttpServletResponse response)
*/
protected void doGet(final HttpServletRequest request,
final HttpServletResponse response)
throws IOException, ServletException {
final String BAR_CODE = request.getParameter("barCode");
response.setContentType("text/html");
final PrintWriter out = response.getWriter();
if (BAR_CODE != null) {
HttpClient client = new DefaultHttpClient();
final String ADDRESS = ServletUtilities.getHttpAddress(BAR_CODE);
out.println("ADDRESS = \"" + ADDRESS + '\"');
HttpGet get = new HttpGet(ADDRESS);
HttpResponse httpResponse = null;
// Removed commented code that will use these objects
}
}
}
] 
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