Tomcat servlet mapping error 404

Question

Sorry if this is a common question, but I'm gonna crazy. I'm starting with JSP developing, using Tomcat running on Ubuntu Server. I'm trying to run my first "Hello World" servlet, without success.

I have the following stuff on the server:

the webapps directory is: /var/lib/tomcat6/webapps/
in webapps I have created the context-root hello/ directory
hello/ contains index.html and WEB-INF/
WEB-INF contains web.xml and classes/HelloServlet.class

This is index.html:

<html>
        <body>
                Click to request the HelloServlet.

                <form action = "/hello/helloworld" method = "get" >
                        <input type = "submit" value = "REQUEST" />
                </form>
        </body>
</html>

This is WEB-INF/web.xml:

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
     version="2.5">

        <servlet>
                <servlet-name>test</servlet-name>
                <servlet-class>HelloServlet</servlet-class>
        </servlet>

        <servlet-mapping>
                <servlet-name>test</servlet-name>
                <url-pattern>/hello/helloworld</url-pattern>
        </servlet-mapping>

</web-app>

and finally this is the source file of HelloServlet:

// HelloServlet.java, a simple Hello World servlet.

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;

public class HelloServlet extends HttpServlet
{
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
        {
                response.setContentType("text/html");
                PrintWriter outputStream = response.getWriter();

                outputStream.println("<html>");

                outputStream.println("<head>");
                outputStream.println("<title>Hello, World!</title>");
                outputStream.println("</head>");

                outputStream.println("<body>");
                outputStream.println("Hello, world! This is my first servlet!");
                outputStream.println("</body>");

                outputStream.println("</html>");

                outputStream.close();
        }
}

The problem is that, on the client side, only http://localhost/hello/ (i.e the index.html page) works. If I click the form-submit button, I get http 404 error (resource not available).

Probably there is an error in servlet-mapping, in the form and/or in web.xml, but I really need help to discover it.

Include the name of the package in the `` tag ex. `org.firstservletapp.HelloServlet` — Meherzad, Mar 21 '13 at 11:47

score 4 · Answer 1 · edited May 23 '17 at 11:45

4

<url-pattern>/hello/helloworld</url-pattern>

You should not include the context path in the servlet's URL pattern. It's already relative to the context root.

Get rid of it.

<url-pattern>/helloworld</url-pattern>

Unrelated to the concrete problem, writing HTML code in a servlet is a very bad practice. For that JSP should be used. See also our own Servlets wiki page which contains sane Hello World examples.

edited May 23 '17 at 11:45

Community

1
1

answered Mar 21 '13 at 13:59

BalusC

1,082,665
372
3,610
3,555

Unfortunately not. I get always a 404 error. Probably I will use JSP in a few time, thanks anyway for the tip. – eang Mar 21 '13 at 19:26

score 1 · Answer 2 · answered Mar 21 '13 at 12:09

1

Add context root to jsp action, below changes might work for you.

<form action = "/hello/hello/helloworld" method = "get" >
  <input type = "submit" value = "REQUEST" />
</form>

answered Mar 21 '13 at 12:09

Avinash K.P

167
7

Unfortunately not. I get always a 404 error. – eang Mar 21 '13 at 19:26
1

@ital Try with just `action="/helloworld"` after having changed your url-pattern to what BalusC said. – Sotirios Delimanolis Mar 22 '13 at 03:00

score 1 · Answer 3 · answered Sep 18 '14 at 13:15

404 may result of :

Bad mapping scenarios (you may have included extra context as answered above or misused wildcards schema)
The servlet has not started (see the startup logs stack in the console or catalina file, you should find your servlet fail exception trace)

score 0 · Answer 4 · answered Mar 07 '16 at 15:50

It took me ages to figure this out. In my case I was getting 404s because I'd failed to appreciate that the Tomcat URLs are case sensitive!

e.g.:

http://server:8080/acme.MyPackage/DoStuff

...404!

http://server:8080/acme.myPackage/DoStuff

...Fine.

Madness.

Tomcat servlet mapping error 404

4 Answers4