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Check if string/object null in query string

Posted on 2004-03-25
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Last Modified: 2010-04-01
If I'm passing a parameter in a query string:

test.jsp?var1=value1

and on the recieving page I get:

String var1 = request.getParameter("var1");

How do I check if no parameter was passed? For example if  this happens:

test.jsp

this checks
if (var1 != null) {}

but what about this case with no value in the query string???
test.jsp?var1=

I thought
 if (var1 != "") {}

 but that doesn't work, what's the check?



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Question by:894359
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5 Comments
 
LVL 14

Expert Comment

by:kennethxu
ID: 10682929
unfortunately its also null.
0
 
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Expert Comment

by:kennethxu
ID: 10682944
in your application, you shoudl thread test.jsp?var1= the same as test.jsp
I always do this check:
if( var1 != null && var1.length() > 0 )
0
 

Author Comment

by:894359
ID: 10683004
I tried the null check and it fails for the second case!
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Accepted Solution

by:
kennethxu earned 250 total points
ID: 10683037
hmm.. did you tried:
if( var1 != null && var1.length() > 0 )
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LVL 14

Expert Comment

by:kennethxu
ID: 10683044
or
if( !var1.equals("") )

it's the same as:

var1.length() > 0
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