Using tag library to check if  a object is null

I would like to use the tag library to see if  the object is null.
The object is set in the session. In my JSP I get the object from the session.
The first thing i want to do is check if it is null- it it is nulll i print a message otherwise i go ahead and do some other stuff
this is what i have:
<logic:equal parameter="customers" value="null">  
      <B> Search string returned 0 records </B>
      </logic:equal>

<logic:notEqual parameter="customers" value="null">  
      //DO HTML STUFF
      </logic:notEqual>

I have a lot of HTML in my JSP - hece i did not use an if-else condition as it was tooconfusing.
Could someone help out with this or give me some info as to how i canuse if-else , i think i am messing up with the braces
thanks