You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
51 lines
1.5 KiB
Java
51 lines
1.5 KiB
Java
Updating session items
|
|
|
|
|
|
|
|
package com.ack.web.servlet;
|
|
|
|
import java.io.IOException;
|
|
import java.io.PrintWriter;
|
|
import javax.servlet.ServletException;
|
|
import javax.servlet.http.HttpServlet;
|
|
import javax.servlet.http.HttpServletRequest;
|
|
import javax.servlet.http.HttpServletResponse;
|
|
import javax.servlet.http.HttpSession;
|
|
|
|
public class UpdatingSessionItems extends HttpServlet {
|
|
public void doGet( HttpServletRequest req, HttpServletResponse res )
|
|
throws ServletException, IOException {
|
|
res.setContentType( "text/html" );
|
|
PrintWriter pw = res.getWriter();
|
|
pw.println( "<HTML><BODY>" );
|
|
|
|
HttpSession theSession = req.getSession();
|
|
|
|
// updated a named item in the session
|
|
synchronized( theSession ) {
|
|
/**
|
|
* when updating items within a session object, you must
|
|
* ensure that you have exclusive access to session object
|
|
* by first synchronizing on the session
|
|
*/
|
|
Integer counter = (Integer) theSession.getAttribute( "counter" );
|
|
|
|
if( counter == null ) {
|
|
theSession.setAttribute( "counter", new Integer( 1 ) );
|
|
}
|
|
else {
|
|
theSession.setAttribute( "counter", new Integer( counter.intValue() + 1 ) );
|
|
}
|
|
|
|
pw.println( "<BR>" + counter );
|
|
/**
|
|
* also note that items inside your session object should really
|
|
* be serializable to ensure that your session can scale within
|
|
* a clustered environment
|
|
*/
|
|
}
|
|
|
|
pw.println( "</BODY></HTML>" );
|
|
}
|
|
}
|