Tomcat Servlet Error 404 - The requested resource is not available

Question

I am completely new to writing a Java Servlet  and 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 in web xml  this section actually doesn t exist in mine  and when I added it the same problem still occurred

User · Answer

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.

User · Answer

try this  if the Java EE V6   package crunch  import java io    import javax servlet    import javax servlet http     WebServlet name  hello  urlPatterns    hello    public class HelloWorld extends HttpServlet     public void doGet HttpServletRequest request                      HttpServletResponse response        throws ServletException  IOException       PrintWriter out   response getWriter        out println  Hello World            now reach the servlet by http   127 0 0 1 8080 yourapp hello  where 8080 is default tomcat port  and yourapp is the context name of your applciation

User · Answer

For those stuck with  The requested resource is not available  in Java EE 7 and dynamic web module 3 x  maybe this could help  the  Create Servlet  wizard in Eclipse  tested in Mars  doesn t create the  Path annotation for the servlet class  but I had to include it to access successfuly to the public methods exposed

User · Answer

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

User · Answer

My problem was in web xml file  In one  lt servlet-mapping gt  there was an error inside  lt url-pattern gt   I forgot to add   before url

User · Answer

You have to user       projectName Filename jsp  in your action attr  or href         contains current folder simple demo project filename jsp     Servlet can only be called with 1 slash forward to your project name

User · Answer

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   lt servlet gt       lt servlet-name gt helloServlet lt  servlet-name gt       lt servlet-class gt crunch HelloWorld lt  servlet-class gt   lt  servlet gt   lt servlet-mapping gt       lt servlet-name gt helloServlet lt  servlet-name gt       lt url-pattern gt  hello lt  url-pattern gt   lt  servlet-mapping gt

[tomcat] Tomcat Servlet: Error 404 - The requested resource is not available

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