Granny's Programming Pearls
"inside of every large program is a small program struggling to get out"
JavaRanch.com/granny.jsp
The moose likes Servlets and the fly likes NullPointerException and request.getParameter() Big Moose Saloon
  Search | Java FAQ | Recent Topics
Register / Login


Win a copy of The Mikado Method this week in the Agile and other Processes forum!
JavaRanch » Java Forums » Java » Servlets
Reply Bookmark "NullPointerException and request.getParameter()" Watch "NullPointerException and request.getParameter()" New topic
Author

NullPointerException and request.getParameter()

harshad kadam
Greenhorn

Joined: Mar 19, 2011
Posts: 8
in servlet i am taking value from URL String callback = request.getParameter("_callback"); problem is &_callback can be there or not, i am getting nullPointerException if &_callback is not there in URL. I tried to catch the exception but didn't work. is there any way to check whether request.getParameter() is null or not? if it is null, i want to execute a part of code and if not, other part.
sudhir nim
Ranch Hand

Joined: Aug 29, 2007
Posts: 212

getParameter returns the value of a request parameter as a String, or null if the parameter does not exist. It does not through NullPointerException if parameter does not exist. Make sure that the request object on which you are calling getParameter is not null. Look at this servlet request Article for details on methods for request parameters.


[Servlet tutorial] [Servlet 3.0 Cook Book]
Mohamed Sanaulla
Bartender

Joined: Sep 08, 2007
Posts: 2928
    
  15

You could do this- callBack != null or callBack == null.


Mohamed Sanaulla | My Blog
harshad kadam
Greenhorn

Joined: Mar 19, 2011
Posts: 8
yes..it worked.. i had written [!callback.equals(null)] i changed it to [callback != null]. resolved.
 
I agree. Here's the link: http://aspose.com/file-tools
 
subject: NullPointerException and request.getParameter()
 
Similar Threads
JSP form processing
null pointer exception after response.sendRedirect() in jsp page.
Null pointer
Problem in updating the fields to database
Error in hashtable put method