0

currently reading Head First Servlet Jsp. I currently stuck in mapping servlet. This is probably a stupid question but how can I map a servlet url pattern properly? I am using eclipse mars and this is my first time with jsp/servlets. I always check the generate web xml when creating a dynamic web project

This is what in the default web.xml 

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://xmlns.jcp.org/xml/ns/javaee"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
    id="WebApp_ID" version="3.1">
    <display-name>HeadFirst</display-name>
    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
        <welcome-file>default.html</welcome-file>
        <welcome-file>default.htm</welcome-file>
        <welcome-file>default.jsp</welcome-file>
    </welcome-file-list>
</web-app>

It runs using this

http://localhost:8080/HeadFirst/Ch2Servlet

but when I add this just below the display name

<servlet>
    <servlet-name>Ch2Servlet</servlet-name>
    <servlet-class>com.test.hello</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>Ch2Servlet</servlet-name>
    <url-pattern>/HelloWorld</url-pattern>
</servlet-mapping>

it gives me a 404 error and this is the url

http://localhost:8080/HeadFirst/servlet/com.test.hello.Ch2Servlet

Here's my servlet class

@WebServlet("/Ch2Servlet")
public class Ch2Servlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        PrintWriter out = response.getWriter();
        java.util.Date today = new java.util.Date();
        out.println("<h1>Hello World</h1>" + "<br>");
        out.println("Date today is " + today + "<br>");
    }
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    }
}

btw i have read this but still am confused Java Servlet URL Mapping Servlet Mapping using web.xml edit added my serlvet class

Community
  • 1
  • 1
Onedaynerd
  • 49
  • 2
  • 9
  • I see you're already using annotations, to change the URL just change the value of `@WebServlet("/Ch2Servlet")`. – Titus Apr 04 '15 at 16:09
  • I tried changing the annotation and this url now works @WebServlet("/HelloWorld") http://localhost:8080/HeadFirst/HelloWorld so do annotation makes url pattern useless or obsolete – Onedaynerd Apr 04 '15 at 16:21
  • You need to restart the server after you change the mapping. Yes the annotation replaces the `web.xml` approach of changing the mapping. – Titus Apr 04 '15 at 16:23
  • So if its servlet version 3 up it recommended to just use annotation instead of mapping? By the way when i remove the annotation i get an error instatiating servlet class – Onedaynerd Apr 04 '15 at 16:30
  • Yes, is easier to set the path using annotation, the error that you get is probably because you have set the wrong `` or `` in the `web.xml` file. – Titus Apr 04 '15 at 16:40

1 Answers1

3

The url is not:

http://localhost:8080/HeadFirst/servlet/com.test.hello.Ch2Servlet

It will be: 

http://localhost:8080/HeadFirst/HelloWorld

More specifically, it will be the value that you set as <url-pattern>...</url-pattern>

Titus
  • 22,031
  • 1
  • 23
  • 33