Getting null value on request.getAttribute

Question

Hi I have a servlet class like this

public class DBConnection extends HttpServlet {
   protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException 
   {

      resp.setContentType("text/html");
      req.setAttribute("Message","Message from servlet page");

      req.getRequestDispatcher("/index.jsp").forward(req,resp);

   }
}

calling servlet on index.jsp page like this

<% String Msg= (String)request.getAttribute("Message");
out.println("<p> Servlet communicated message to JSP: "+ Msg + "</p>");%>

This in my web.xml file

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"   xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
    <display-name>dbconnection</display-name>
    <welcome-file-list>
    <welcome-file>Login.html
    </welcome-file>
    </welcome-file-list>

    <servlet>
        <servlet-name>DBConnection</servlet-name>
        <servlet-class>DBConnection</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>DBConnection</servlet-name>
        <url-pattern>/DBConnection</url-pattern>
    </servlet-mapping>
</web-app>

I am getting a null value .. can anyone help me?

reading this might be of some help http://stackoverflow.com/a/2125045/1851302 — KNU, Apr 10 '14 at 11:59

score 1 · Answer 1 · answered Apr 10 '14 at 12:35

1

You are getting null value because you are not accessing with right url.

Suppose you have url like following:

http://localhost:8080/TestWeb/

where your project name is TestWeb. If you had tried with above url you are getting null value because request is not comming from servlet. So you need to use like following url

http://localhost:8080/TestWeb/DBConnection

Then only you will get right output. Please try it.

answered Apr 10 '14 at 12:35

Yubaraj

3,800
7
39
57

Thanks a lot.. there is a mistake in accessing right url – user123 Apr 11 '14 at 07:07
@user123. Its my pleasure. – Yubaraj Sep 08 '14 at 07:04

GbGbGbGbEB · Accepted Answer · 2014-04-10T11:54:59.393

0

You can access the attributes defined in the servlet using Expression Language.

Inside JSP:

<p> Servlet communicated message to JSP: ${Message} </p>

Servlet:

RequestDispatcher rd;
resp.setContentType("text/html");
req.setAttribute("Message","Message from servlet page");
rd = req.getRequestDispatcher("/index.jsp");
rd.forward(req,resp);

edited Apr 10 '14 at 11:54

answered Apr 10 '14 at 11:45

GbGbGbGbEB

56
1
6

still getting the null value – user123 Apr 10 '14 at 11:47
Sorry, when you said you were getting a null value I though you could see the page but not the message. Make sure you have full for DBConnection If DBConnection is inside a package, you need to specify that. eg. pack.com.DBConnection – GbGbGbGbEB Apr 10 '14 at 12:46
Also the url pattern should be either accessed through the address bar or linked to by a form for example. '
' – GbGbGbGbEB Apr 10 '14 at 12:52

score 0 · Answer 3 · edited Apr 10 '14 at 13:26

You are not calling your servlet in url that you are trying to invoke Try as suggested by Yubi.

Example: If your url pattern is

<url-pattern>/TestingServlet</url-pattern>

in your web.xml to execute your servlet get/post in that servlet u should use urlpattern

    `http://yourserverhost:port/ServletTest/TestingServlet`

ServletTest is your application context and TestingServlet is your url pattern for your Servlet.

  <servlet>
    <description></description>
    <display-name>TestingServlet</display-name>
    <servlet-name>TestingServlet</servlet-name>
    <servlet-class>TestingServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>TestingServlet</servlet-name>
    **<url-pattern>/TestingServlet</url-pattern>**
  </servlet-mapping>

Getting null value on request.getAttribute

3 Answers3