Post parameters are becoming null (at random)

Posted by Raghuram Duraisamy on Stack Overflow See other posts from Stack Overflow or by Raghuram Duraisamy
Published on 2009-12-27T14:41:35Z Indexed on 2010/03/11 4:39 UTC
Read the original article Hit count: 562

Hi,

My web application is developed with Struts2 and it was working fine till recently. All of a sudden one of the modules has started malfunctioning.

The malfunctioning module is 'Update Student details' page. This page has a lot of fields like 'schoolName', 'degreeName', etc .

School 1: <input name="schoolName">

School 2: <input name="schoolName">

..... 
School n: <input name="schoolName">

As mentioned earlier, the page was working perfectly fine till recently. Now, one/many of the values of 'schoolName', 'degreeName', etc are being received as "" (EMPTY STRING) on the server-side.

For debugging, I used firebug and remote-debugging in eclipse. I find that the post-parameters are correct on the client-side. For instance, during one of the submissions the post-parameters were as below (i noted them from firebug).

Content-Type: multipart/form-data; boundary=---------------------------2921238217421 
Content-Length: 48893 

<OTHER_PARAMETERS> <!--Truncated for clarity --> 

-----------------------------2921238217421 
Content-Disposition: form-data; name="schoolName" 

ABC Institute 
-----------------------------2921238217421 
Content-Disposition: form-data; name="schoolName" 

Test School 
-----------------------------2921238217421 
Content-Disposition: form-data; name="schoolName" 

XYZ 
-----------------------------2921238217421 
Content-Disposition: form-data; name="schoolName" 

Texas Institute 
-----------------------------2921238217421 
Content-Disposition: form-data; name="schoolName" 

XXXX School 

-----------------------------2921238217421-- 

But on the server-side, the request params were as below:

schoolName=[ABC Institute, Test School, XYZ, , XXXX School], 

"Texas Institute" was received as "" (EMPTY STRING) in this particular case. This is not happening consistently. The parameters that become NULL (or EMPTY STRING) seem random to me - during one instance, parameter schoolName[3] became null as illustrated above, parameter schoolName[2] became null during yet another submission, etc. At times, none of the parameters are nullified.

The following is the list of the interceptors in the action definition.

List of interceptors: 
----------------------
FileUploadInterceptor
org.apache.struts2.interceptor.FileUploadInterceptor
ServletConfigInterceptor
org.apache.struts2.interceptor.ServletConfigInterceptor  StaticParametersInterceptor
com.opensymphony.xwork2.interceptor.StaticParametersInterceptor
ParametersInterceptor
com.opensymphony.xwork2.interceptor.ParametersInterceptor
MyCustomInterceptor
com.xxxx.yyyy.interceptors.GetLoggedOnUserInterceptor

This issue appears rather weird to me and I have not been able to zero-in on the exact cause of the issue. Any help in this regard would be highly appreciated. Thanks in advance.

Thanks, Raghuram

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