import javax.servlet.ServletContextAttributeEvent; import javax.servlet.ServletContextAttributeListener; import javax.servlet.annotation.WebListener; @WebListener public class ContextAttrListener implements ServletContextAttributeListener { @Override public void attributeAdded(ServletContextAttributeEvent event) { System.out.println("Attribute " + event.getName() + " Added"); } @Override public void attributeRemoved(ServletContextAttributeEvent event) { System.out.println("Attribute " + event.getName() + " Removed"); } @Override public void attributeReplaced(ServletContextAttributeEvent event) { System.out.println("Attribute " + event.getName() + " Replaced"); } }
import java.io.IOException; import java.io.PrintWriter; import javax.servlet.annotation.WebServlet; import javax.servlet.http.*; import javax.servlet.*; @WebServlet(urlPatterns = {"/SampleApp"}) public class SampleApp extends HttpServlet { @Override public void doGet(HttpServletRequest req, HttpServletResponse res)throws IOException{ try(PrintWriter out = res.getWriter()){ ServletContext context = req.getServletContext(); System.out.println("Adding Attribute to Servlet Context"); context.setAttribute("myName", "Krishna"); System.out.println("Replacing Attribute from Servlet Context"); context.setAttribute("myName", "abcd"); System.out.println("Removing Attribute from Servlet Context"); context.removeAttribute("myName"); } } }
Run
' SampleApp', server console has
messages like below.
Info: Attribute myName Added Info: Replacing Attribute from Servlet Context Info: Attribute myName Replaced Info: Removing Attribute from Servlet Context Info: Attribute myName Removed
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