Error 404: The requested resource is not available using HelloWorld servlet
Solution 1
You definitely need to map your servlet onto some URL. If you use Java EE 6 (that means at least Servlet API 3.0) then you can annotate your servlet like
@WebServlet(name="helloServlet", urlPatterns={"/hello"})
public class HelloWorld extends HttpServlet {
//rest of the class
Then you can just go to the localhost:8080/yourApp/hello
and the value should be displayed. In case you can't use Servlet 3.0 API than you need to register this servlet into web.xml
file like
<servlet>
<servlet-name>helloServlet</servlet-name>
<servlet-class>crunch.HelloWorld</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>helloServlet</servlet-name>
<url-pattern>/hello</url-pattern>
</servlet-mapping>
Solution 2
Writing Java servlets is easy if you use Java EE 7
@WebServlet("/hello-world")
public class HelloWorld extends HttpServlet {
@Override
public void doGet(HttpServletRequest request,
HttpServletResponse response) {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("Hello World");
out.flush();
}
}
Since servlet 3.0
The good news is the deployment descriptor is no longer required!
Read the tutorial for Java Servlets.
Solution 3
this is may be due to the thing that you have created your .jsp or the .html file in the WEB-INF instead of the WebContent folder.
Solution: Just replace the files that are there in the WEB-INF folder to the Webcontent folder and try executing the same - You will get the appropriate output
Tom Haddad
Updated on May 06, 2021Comments
-
Tom Haddad about 3 years
I am writing a Java Servlet, and I am struggling to get a simple
HelloWorld
example to work properly.The
HelloWorld.java
class is:package crunch; import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class HelloWorld extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { PrintWriter out = response.getWriter(); out.println("Hello World"); } }
I am running Tomcat v7.0, and have already read similar questions, with responses referring to changing the
invoker
servlet-mapping
section inweb.xml
. This section actually doesn't exist in mine, and when I added it the same problem still occurred.