Java Servlet, http status 404, The requested resource is not available

Question

I am trying to create a servlet in java, using Eclipse IDE and Tomcat7 server. When I run the HelloForm in server it shows the form but after entering numbers and clicking submit it shows:

HTTP Status 404 - /Test2/HelloWorld

type Status report

message /Test2/HelloWorld

description The requested resource is not available.

Apache Tomcat/7.0.47

Code for HelloForm.html

<!DOCTYPE html>
<html>
<body>
    <form action="HelloWorld" method="post">
        Enter 1st number : <input type="text" name="num1"> <br>
        Enter 2st number : <input type="text" name="num2"> <br> <input
            type="submit">
    </form>
</body>
</html>

Code for HelloWorld.java

package mypkg;

public class HelloWorld extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        int num1 = Integer.parseInt(request.getParameter("num1"));
        int num2 = Integer.parseInt(request.getParameter("num2"));
        int sum = num1 + num2;
        System.out.println(sum);
        PrintWriter out = response.getWriter();
        out.println("Addition : " + sum);
    }
}

Code for web.xml

<?xml version="1.0" encoding="UTF-8"?> 

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance "xmlns= "http://java.sun.com/xml/ns/javaee" xsi: schemaLocation ="http: //java.sun.com/ xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0">

    <servlet>
        <servlet-name>HelloWorldServlet</servlet-name>
        <servlet-class>mypkg.HelloWorld</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>HelloWorldServlet</servlet-name>
        <url-pattern>/sayhello</url-pattern>
    </servlet-mapping>

</web-app>

Arvind Kumar Avinash · Accepted Answer · 2020-01-12T23:35:42.433

You have missed @WebServlet("/HelloWorld"). Given below is the completed code:

package mypkg;

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;

@WebServlet("/sayhello")
public class HelloWorld extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        int num1 = Integer.parseInt(request.getParameter("num1"));
        int num2 = Integer.parseInt(request.getParameter("num2"));
        int sum = num1 + num2;
        System.out.println(sum);
        PrintWriter out = response.getWriter();
        out.println("Addition : " + sum);
    }
}

Make sure you have the following root declaration of your web.xml otherwise it will not be interpreted as Servlet 3.0 which supports @WebServlet annotation.

<web-app 
    xmlns="http://java.sun.com/xml/ns/javaee"
    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_3_0.xsd"
    version="3.0">

Update:

I can see that you have now added the content of your web.xml in the question. As per this update, your HTML form action should be as follows:

<form action="sayhello" method="post">

i tried this but it says that javax.servlet.annotation cannot be resolved — Amel B, Jan 12 '20 at 22:08
i already have added the web.xml specifying also servlet name and servlet mapping but it still does not work — Amel B, Jan 12 '20 at 22:21
Have you included Apache tomcat runtime in project facets in eclipse? Because servlet jars are provided by the container itself. — Dark Matter, Jan 12 '20 at 23:19

Java Servlet, http status 404, The requested resource is not available

1 Answers1