setting http Header using urlconnection

[Maggie Taylor]

I have a servlet that recives http header information from a client program.

Now I have observed that when I assign a string value (including empty string ) in conn.addRequestProperty(), then the program works good. But, when I assign a null as any header value, then even the next header value displays a null even if I have assigned a value to it.


Here's a snippet from the client program:

    
 
 URL url = new URL ("http://localhost:8080/example1/displayservlet");
 
 URLConnection conn = url.openConnection();
 
 conn.setAllowUserInteraction(false);        
 conn.setDoOutput(true); 
 
  conn.addRequestProperty("file","abcd.xml");
  conn.addRequestProperty("center",null);
  conn.addRequestProperty("key","xyz");
  conn.addRequestProperty("id","ew3456");
  conn.addRequestProperty("version","3.0");
 

A snippet from the servlet:

 
String file = request.getHeader("file");
out.println("file = "+file);  // displays abcd.xml
String center = request.getHeader("center");
out.println("center= "+center); //displays null
String key = request.getHeader("key");
out.println("key = "+key); //displays null even though xyz has been set in the client program !!!
String id = request.getHeader("id");
out.println("id = "+id); // displays ew3456
String version = request.getHeader("version"); 
out.println("version = "+version); // displays 3.0
 

Can anybody help me in figuring out why this is happening ? I'm working on JDeveloper / Tomcat server.

Thanks.
Maggie

[William Brogden]

What exactly are you trying to accomplish by setting the property to null?
I would guess that you have broken the request header mechanism and an incomplete set of headers is sent - can you look at the actual headers transmitted with TCPMON or similar mechanism?
Bill

[Maggie Taylor]

Originally posted by William Brogden:
What exactly are you trying to accomplish by setting the property to null?

Thanks for replying Bill. I am testing the application for all different values - which include all these:
1)assigning a string as value
conn.addRequestProperty("file","abcd.xml");
2)assinging an empty String as value
conn.addRequestProperty("file","");
3)assinging a null as value
conn.addRequestProperty("file",null);

and the program is breaking down for the 3rd condition - showing null for next header value as well.

Maggie

[Rashid Mayes]

Hello, It may be better not to set the header at all if you want the value to be null. Try something similar to:

    
if ( file != null )
{
   conn.addRequestProperty("file",file);
}