了解web.xml

Question

I am trying to create a dynamic web project using eclipse.This is the first time I am working on servlets and jsp.

I have created a page and it works fine. However I am not able to understand the web.xml page entirely. As far as I have read and searched that <url-pattern> under <servlet-mapping> is used by the client to access your servlet. However whatever I change my <url-pattern> to,it seems to only access the servlet through servlet class name.

  <display-name>CustomerManagment1</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>
  <servlet>
  <servlet-name>Welcome Page</servlet-name>
  <servlet-class>WelcomePage</servlet-class>
  </servlet>

  <servlet-mapping>
  <servlet-name>Welcome Page</servlet-name>
  <url-pattern>/welcomepage.jsp</url-pattern>
  </servlet-mapping>
</web-app>

The browser complaints when I use http://host-name/CustomerManagment1/welcompage.jsp

However if use this http://host-name/CustomerManagment1/WelcomePage , it works fine. What am I missing here?

Answer 1

Have you written a JSP or a servlet? I am a little bit confused If you are using a JSP, then the servlet tag should be like

<servlet>
<description></description>
<display-name>WelcomePage</display-name>
<servlet-name>WelcomePage</servlet-name>
<jsp-file>/WelcomePage.jsp</jsp-file>
</servlet>

If you are using servlet , then your tag is fine.

In case of url-pattern, are you sure you have not written any annotation for the WelcomPage servlet class? If you are using Tomcat 7 or any java EE 6 container, then creating a new servlet through eclipse will create a default @WebServlet annotation and add to the servlet as follows.

@WebServlet("/WelcomePage")
public class WelcomePage extends HttpServlet {}

This means that your url pattern is being picked from here.