how to get websphere port number

Please provide more information.

You want a Java Application that is running on a WebSphere JVM to determine
the port number that was used to access the resource.  Is this correct?

i got a java application, this is to get the port number of websphere application.
but how to get?

I'm sorry, I must not have been clear enough with my question.

Are you asking:

How should a Java application running on a WebSphere Application Server determine the port number being used?

If this is the case, you need to look into the available on-line documentation that talks about developing Administrative programs in Java.

http://publib.boulder.ibm.com/infocenter/wasinfo/v5r1//index.jsp?topic=/com.ibm.websphere.base.doc/info/aes/ae/welcadminprogram.html

You probably will want to investigate the section entitled:
Create a custom Java admininstrative client program using the Java administrative APIs
http://publib.boulder.ibm.com/infocenter/wasinfo/v5r1//topic/com.ibm.websphere.base.doc/info/aes/ae/tjmx_customjava.html

Is this what you want/need?

firstly
when a WebSphere Application Server run,
we can access it by
http://127.0.0.1:9080/myweb or
http://127.0.0.1:9081/myweb  right?

so now my question, my servlet or any java class, how do i know which one above is running?