Kai Karius

Can it be that the session gets created with the first request and the Listener gets called THEN?

Hi people,

I created a HttpSessionListener that should create a folder on the HD everytime a session opens. Unfortunately that does not seem to work:

package com.hatlessduck.web; import java.io.File; import java.io.IOException; import javax.servlet.annotation.WebListener; import javax.servlet.http.HttpSession; import javax.servlet.http.HttpSessionEvent; import javax.servlet.http.HttpSessionListener; import org.apache.tomcat.util.http.fileupload.FileUtils; @WebListener public class SessionListener implements HttpSessionListener { public SessionListener() { super(); } @Override public void sessionCreated(HttpSessionEvent arg0) { System.out.println("ServletContextListener destroyed"); HttpSession session = arg0.getSession(); String resourcesPath = (String)session.getServletContext().getAttribute("resourcePath"); String sessionId = (String)session.getId(); new File(resourcesPath+"/"+sessionId+"/").mkdirs(); } @Override public void sessionDestroyed(HttpSessionEvent event) { HttpSession session = event.getSession(); String resourcesPath = (String)session.getServletContext().getAttribute("resourcePath"); String sessionId = (String)session.getId(); try { FileUtils.deleteDirectory(new File(resourcesPath+"/"+sessionId)); } catch (IOException e) {e.printStackTrace();} } }

So, what am I doing wrong? Btw I started Tomcat as administrator.

Thank you!

Sigh. Yes. That was it.

Thank you!

The mentioned class is missing in the classpath of the runtime environment. Add it to the classpath of the runtime environment.

True. But it IS there, i will give you an overview of my deployment structure:

[tomcat]/webapps/Listener/WEB-INF/web.xml
[tomcat]/webapps/Listener/WEB-INF/com/example/Dog.class
tomcat]/webapps/Listener/WEB-INF/com/example/MyServletContextListener.class
tomcat]/webapps/Listener/WEB-INF/com/example/ListenerTester.class

So, whats the matter?

Hi Guys,

ok, i wrote a listener, here it is:

package com.example; import javax.servlet.*; public class MyServletContextListener implements ServletContextListener { public void contextInitialized(ServletContextEvent event) { ServletContext sc = event.getServletContext(); String dogBreed = sc.getInitParameter("breed"); Dog d = new Dog(dogBreed); sc.setAttribute("dog",d); } public void contextDestroyed(ServletContextEvent event) { } }

Its from the HF Servlet and JSP as some of you will guess. Its deployed in [tomcat]/webapps/Listener/WEB-INF/com/example. The DD is such:

<web-app xlmns="http://java.sun.com/xml/ns/j2ee" xlmns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" version="2.4"> <servlet> <servlet-name>ListenerTester</servlet-name> <servlet-class>com.example.ListenerTester</servlet-class> </servlet> <servlet-mapping> <servlet-name>ListenerTester</servlet-name> <url-pattern>/ListenTest.do</url-pattern> </servlet-mapping> <context-param> <param-name>breed</param-name> <param-value>Dackel</param-value> </context-param> <listener> <listener-class> com.example.MyServletContextListener </listener-class> </listener> </web-app>

Its deployed in tomcat]/webapps/Listener/WEB-INF

Now upon startup Tomcat 5 tells me very inconclusive stuff:

08.02.2009 17:52:48 org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: contextDestroyed()
08.02.2009 17:52:48 org.apache.catalina.core.ApplicationContext log
INFO: ContextListener: contextDestroyed()
08.02.2009 17:52:49 org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: contextDestroyed()
08.02.2009 17:52:49 org.apache.catalina.core.ApplicationContext log
INFO: ContextListener: contextDestroyed()
08.02.2009 17:52:50 org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: contextDestroyed()
08.02.2009 17:52:50 org.apache.catalina.core.ApplicationContext log
INFO: ContextListener: contextDestroyed()
08.02.2009 17:53:37 org.apache.catalina.core.ApplicationContext log
INFO: org.apache.webapp.balancer.BalancerFilter: init(): ruleChain: [org.apache.webapp.balancer.RuleChain: [org.apache.webapp.balancer.rules.URLStringMatchRule: Target string: News / Redirect URL: http://www.cnn.com], [org.apache.webapp.balancer.rules.RequestParameterRule: Target param name: paramName / Target param value: paramValue / Redirect URL: http://www.yahoo.com], [org.apache.webapp.balancer.rules.AcceptEverythingRule: Redirect URL: http://jakarta.apache.org]]
08.02.2009 17:53:39 org.apache.catalina.core.ApplicationContext log
INFO: ContextListener: contextInitialized()
08.02.2009 17:53:39 org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: contextInitialized()
08.02.2009 17:53:42 org.apache.catalina.core.ApplicationContext log
INFO: ContextListener: contextInitialized()
08.02.2009 17:53:42 org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: contextInitialized()
08.02.2009 17:53:42 org.apache.catalina.core.StandardContext listenerStart
SCHWERWIEGEND: Error configuring application listener of class com.example.MyServletContextListener
java.lang.ClassNotFoundException: com.example.MyServletContextListener
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1387)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1233)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:3786)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4342)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:525)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:926)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:889)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:492)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1149)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:311)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:719)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
at org.apache.catalina.core.StandardService.start(StandardService.java:516)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
at org.apache.catalina.startup.Catalina.start(Catalina.java:578)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)
08.02.2009 17:53:42 org.apache.catalina.core.StandardContext listenerStart
SCHWERWIEGEND: Skipped installing application listeners due to previous error(s)
08.02.2009 17:53:44 org.apache.catalina.core.ApplicationContext log
INFO: ContextListener: contextInitialized()
08.02.2009 17:53:44 org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: contextInitialized()

Where seems to be the error?

TWERP

Hi!

Tanks, i checked the statement. Ofc, it should read:

<%@ page import="java.util.*" %>

Guess i was so glad to see some familiar Java that i didnt consider the differences.

Thank you very much,

TWERP

First off,

relax. I didnt fail completely . Its just the last step involving an actual JSP file that troubles me. My deployment structure is as given in the book. Each of the previous examples worked fine. Now, building in the result.jsp my fox gives me the following:

org.apache.jasper.JasperException: /result.jsp(1,5) Invalid directive org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:40) org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:407) org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:88) org.apache.jasper.compiler.Parser.parseDirective(Parser.java:517) org.apache.jasper.compiler.Parser.parseElements(Parser.java:1444) org.apache.jasper.compiler.Parser.parse(Parser.java:138) org.apache.jasper.compiler.ParserController.doParse(ParserController.java:216) org.apache.jasper.compiler.ParserController.parse(ParserController.java:103) org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:154) org.apache.jasper.compiler.Compiler.compile(Compiler.java:315) org.apache.jasper.compiler.Compiler.compile(Compiler.java:295) org.apache.jasper.compiler.Compiler.compile(Compiler.java:282) org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:586) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:317) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267) javax.servlet.http.HttpServlet.service(HttpServlet.java:717) com.example.web.BeerSelect.doPost(BeerSelect.java:24) javax.servlet.http.HttpServlet.service(HttpServlet.java:637) javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

Now, i cant get smart of this....Here are my files:

Its the BeerExpert.java :

package com.example.model; import java.util.*; public class BeerExpert { public List getBrands(String color) { List brands = new ArrayList(); if (color.equals("amber")) { brands.add("Jack Amber"); brands.add("Red Moose"); } else { brands.add("Jail Pale Ale"); brands.add("Gout Stout"); } return (brands); } }

The BeerSelect.java

package com.example.web; import javax.servlet.*; import javax.servlet.http.*; import java.io.*; import java.util.*; import com.example.model.*; public class BeerSelect extends HttpServlet { public void doPost (HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { String c = request.getParameter("color"); BeerExpert be = new BeerExpert(); List result = be.getBrands(c); request.setAttribute("styles", result); RequestDispatcher view = request.getRequestDispatcher("result.jsp"); view.forward (request, response); } }

The web.xml

<web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XML-Schema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" version="2.4"> <servlet> <servlet-name>Ch3Beer</servlet-name> <servlet-class>com.example.web.BeerSelect</servlet-class> </servlet> <servlet-mapping> <servlet-name>Ch3Beer</servlet-name> <url-pattern>/SelectBeer.do</url-pattern> </servlet-mapping> </web-app>

And, ofc. the result.jsp

<%@ import="java.util.*" %> <html> <body> <h1 align="center">Beer Recommendations JSP</h1> <% List styles = (List)request.getAttribute("styles"); Iterator it = styles.iterator(); while(it.hasNext()) { out.print("<br>try: " + it.next()); } %> </body> </html>

Thanks in advance.