passing variable from servlet to jsp doesn't work

Question

I have problem with passing an object from servlet to jsp.

Servlet.java

    @Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    Controller test = new Controller();
    test.setObjects();
    request.getSession().setAttribute("item", test.node_1);
    request.getRequestDispatcher("index.jsp").forward(request, response);
}

index.jsp

<title> ${item.firstName} </title>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
    <servlet>
        <servlet-name>Servlet</servlet-name>
        <servlet-class>socialgraphui.Servlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>Servlet</servlet-name>
        <url-pattern>/Servlet</url-pattern>
    </servlet-mapping>
    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
</web-app>

Tomcat output

okt 25, 2014 6:17:14 PM org.apache.catalina.startup.HostConfig deleteRedeployResources
    INFO: Undeploying context []
    okt 25, 2014 6:17:14 PM org.apache.catalina.startup.HostConfig deployDescriptor
    INFO: Deploying configuration descriptor /Library/Java/Servers/apache-tomcat-7.0.42/conf/Catalina/localhost/ROOT.xml
    okt 25, 2014 6:17:14 PM org.apache.catalina.util.LifecycleBase start
    INFO: The start() method was called on component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[]] after start() had already been called. The second call will be ignored.

In browser console is no error or warning message. Could you please help me how can i find out what is wrong?

Seems fine to me, does your object has getters for the attribute you are asking or/and are you sure it has the name set? — KBorja, Oct 25 '14 at 16:30
@KBorja Actually I am not sure if name of object is set. I tried to debug the application and set a breakpoint in Servlet.java class in doGet method, but it didn't stop at breakpoint. I am new in java ee and i am not sure if doGet method is called after project running. — Matt, Oct 25 '14 at 16:45
@KBoja if object have no getter it will produce javax.el.PropertyNotFoundException for Matt to execute doGet method according your config you should follow this adress 'http://localhost:8080/your project name/Servlet' — njjnex, Oct 25 '14 at 16:47
Make a little test, pass one string to the session so you can see if your server is working... — KBorja, Oct 25 '14 at 18:05
possible duplicate of [Pass variables from servlet to jsp](http://stackoverflow.com/questions/3608891/pass-variables-from-servlet-to-jsp) — Gas, Oct 25 '14 at 20:38
@KBorja I tried tmarwen's answer, but result is the same. In title is nothing. — Matt, Oct 26 '14 at 08:04
@njjnex So if I want to execute doGet method, i have to use localhost:8080/my project name/Servlet address? Because i use localhost:8080 address nad when i want to use localhost:8080/my project name/Servlet I got http status 404 — Matt, Oct 26 '14 at 08:10

njjnex · Accepted Answer · 2014-10-26T13:18:09.970

3

Check URL you follow it should be:

http://localhost:8080/your project name/Servlet

Also if item.getFirstName returns null you will see nothing in tags

To be sure that your param passing to jsp page change item value for String for example

request.getSession.setAttribute('item' , 'my title');

Now if you will see my title in <title> tag than passing param done and reason in your object.

edited Oct 26 '14 at 13:18

answered Oct 25 '14 at 16:52

njjnex

1,490
13
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I got http status 404 and yes, in tags is nothing – Matt Oct 25 '14 at 16:56
If i open http://localhost:8080/your project name/Servlet i get http status 404. For project i use http://localhost:8080/ address – Matt Oct 25 '14 at 17:05
try <%= session.getAttribute("item") %> and see if that is null or not. if it is not, then as njjnex says, getFirstName may return a null value. – Joeblade Oct 25 '14 at 17:24
(your project name) - replace with name of your project – njjnex Oct 25 '14 at 17:25
@Joeblade <%= session.getAttribute("item") %> return null – Matt Oct 25 '14 at 17:31
@njjnex yes, i replaced it with the name of my project – Matt Oct 25 '14 at 17:32
please post full url you access this page. – njjnex Oct 25 '14 at 17:39
@njjnex socialgraphui is the name of project, http://localhost:8080/socialgraphui/Servlet – Matt Oct 25 '14 at 17:45
1

can you test your 'test.node_1' object I sure it's null – njjnex Oct 25 '14 at 18:13
agree with @njjnex, test the basics first. you can also set a second variable, session.setAttribute("testvalue", "somestring") and try to print that in your page. when in doubt, verify your basic assumptions – Joeblade Oct 25 '14 at 18:14
@Joeblade I used wrong address, it works with localhost:8080/Servlet address – Matt Oct 26 '14 at 08:21

score 2 · Answer 2 · answered Oct 25 '14 at 18:16

2

Make sure your JSP is allowed to access the Session request object by setting below parameter on top of your JSP page:

<%@ page session="true" %>

And to avoid HTML illegal chars, it would be better to use el:

<title>
  <c:out value="${sessionScope.item.firstName}"/>
</title>

Note: To use the c (core) JSTL, you must import the tag library by declaring below code on top of you JSP page:

<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>

answered Oct 25 '14 at 18:16

tmarwen

15,750
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I tried it, but result is still the same. In title is nothing. – Matt Oct 26 '14 at 08:01
Coudl you provide a sample web app and host it in some remote code storage provider, Github may be. It would be easier to read. You may need to describe what your `item` object referer class is and what `node_1` is! – tmarwen Oct 26 '14 at 10:26
I am sorry i tried it with wrong address. It works with localhost:8080/Servlet address – Matt Oct 26 '14 at 20:23
Could you accept the answer and upvote it if it helped resolving the issue? – tmarwen Oct 26 '14 at 22:27
Thanks for help, but actually njjnex's answer helped me solve the problem, but i can at least upvote – Matt Oct 27 '14 at 08:08

score 0 · Answer 3 · answered Oct 25 '14 at 17:56

0

You are setting the object in the session scope. So you may wanna use sessionscope to retrive the value:

<title>${sessionScope.item.firstName}</title>

answered Oct 25 '14 at 17:56

Sas

2,473
6
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Result is the same. In title tag is nothing. – Matt Oct 25 '14 at 18:00

passing variable from servlet to jsp doesn't work

3 Answers3