page is not redirect

Question

org.apache.jasper.JasperException: Exception in JSP: /views/header.jsp:14

11:         <a href="<%=request.getContextPath()%>">Home</a> | 
12:         <% String username=(String)session.getAttribute("formdata");
13:         String admin="admin";
14:         if(username.equals(" ")){
15:             
16:             String logout="http://localhost:8080/NewsBank/logout.do";
17:             response.sendRedirect(logout);

Stacktrace:

    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:451)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:373)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:321)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:257)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
    org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:250)
    org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1063)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:801)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:549)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:627)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)

root cause

java.lang.NullPointerException
    org.apache.jsp.views.addStory_jsp._jspService(addStory_jsp.java:93)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:321)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:257)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
    org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:250)
    org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1063)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:801)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:549)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:627)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)

in this code i dont get redirect to asking page..ie logout page — Rakesh Sahu, Apr 29 '11 at 07:09
perhaps you should be null checking the username variable... — stevevls, Apr 29 '11 at 07:13

score 3 · Accepted Answer · edited May 23 '17 at 12:13

3

username seems null to me.

Check for nullity

if(username != null || "".equals(userName)){
//your code
}

Suggestions:

We have Filter for this (authentication check) purpose why spoiling jsp ?
Avoid writing javacode on JSP

See Also

edited May 23 '17 at 12:13

Community

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answered Apr 29 '11 at 07:13

jmj

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+1 not only for the right answer, but also for the good way. Good. – Mudassir Apr 29 '11 at 07:17
i have 3 diffrent cases in the header page ..ie 1)if(username.isEmpty()){ //redirect to index page } 2)else if(username.equals(admin)){ //redirect to admin page } 3)else if(username!=admin && username!=""){//redirect to all user page} – Rakesh Sahu Apr 29 '11 at 07:42
1. check for nullity 2. you can compare string using `equals()` not using `==` 3. read out *Suggestions* section – jmj Apr 29 '11 at 07:44
means in case of username==null then it must have redirect to index page......... to which it is not redirect now – Rakesh Sahu Apr 29 '11 at 07:45
`username == null` if this returns true it says that you don't have username set in session so it should go to login page I guess – jmj Apr 29 '11 at 07:46
yes...but how redirect to that page i use response.sendRedirect(request.getContextPath()); in this block but not working gives above error.... i used index.jsp, index.do, logout.do almost everything in paramaeter of the sendRedirect – Rakesh Sahu Apr 29 '11 at 08:00
yes Jigar...you r true...but i did not getting to it in right way or u have to say some more abt it...actully i used one line before for assigning a value of the code in to a variable so that it went to nullPointerExecption everytime.....it did not came to if(){} block...well thank you very much jigar....i got solution – Rakesh Sahu Apr 29 '11 at 08:45

page is not redirect

1 Answers1