Servlet Http Session Attribute Listener project

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package com.cv.servlet.session.listener; /**  * @author Chandra Vardhan  *  */ public class Dog {      private String name;   public String getName() {     return name;   }   public void setName(String name) {     this.name = name;   }   public Dog(String name) {     this.name = name;   } }

/**  *   */ package com.cv.servlet.session.listener; import javax.servlet.http.HttpSessionAttributeListener; import javax.servlet.http.HttpSessionBindingEvent; import org.apache.log4j.Logger; /**  * @author Chandra Vardhan  *  */ public class HttpSessionAttributeListenerImpl implements     HttpSessionAttributeListener {   private static final Logger LOGGER = Logger       .getLogger(HttpSessionAttributeListenerImpl.class);   /**    *     */   public HttpSessionAttributeListenerImpl() {   }   /*    * (non-Javadoc)    *     * @see    * javax.servlet.http.HttpSessionAttributeListener#attributeAdded(javax.    * servlet.http.HttpSessionBindingEvent)    */   @Override   public void attributeAdded(HttpSessionBindingEvent httpSessionBindingEvent) {     LOGGER.info("Entered into attributeAdded(-) of HttpSessionAttributeListenerImpl class... ");     Dog dog = (Dog) httpSessionBindingEvent.getValue();     LOGGER.info("Value of the context attribute is : " + dog.getName());     LOGGER.info("Checking whether it is stored as context attribute : "         + httpSessionBindingEvent.getSession().getAttribute("dog"));     dog.setName("Tommy is the second pet name...");     httpSessionBindingEvent.getSession().setAttribute("dog", dog);   }   /*    * (non-Javadoc)    *     * @see    * javax.servlet.http.HttpSessionAttributeListener#attributeRemoved(javax    * .servlet.http.HttpSessionBindingEvent)    */   @Override   public void attributeRemoved(HttpSessionBindingEvent httpSessionBindingEvent) {     LOGGER.info("Entered into attributeRemoved(-) of HttpSessionAttributeListenerImpl class... ");     Dog dog = (Dog) httpSessionBindingEvent.getValue();     if (dog != null) {       LOGGER.info("Value of the context attribute is : " + dog.getName());     }   }   /*    * (non-Javadoc)    *     * @see    * javax.servlet.http.HttpSessionAttributeListener#attributeReplaced(javax    * .servlet.http.HttpSessionBindingEvent)    */   @Override   public void attributeReplaced(HttpSessionBindingEvent httpSessionBindingEvent) {     LOGGER.info("Entered into attributeReplaced(-) of HttpSessionAttributeListenerImpl class... ");     Dog dog = (Dog) httpSessionBindingEvent.getValue();     if (dog != null) {       LOGGER.info("Value of the context attribute is : " + dog.getName());       LOGGER.info("Checking whether it is stored as context attribute : "           + httpSessionBindingEvent.getSession().getAttribute("dog"));     }   } }

package com.cv.servlet.session.listener; 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; import org.apache.log4j.Logger; /**  * Servlet implementation class HttpSessionListenerServlet  *   * @author Chandra Vardhan  *  */ public class HttpSessionListenerServlet extends HttpServlet {      private static final Logger LOGGER = Logger.getLogger(HttpSessionListenerServlet.class);      private static final long serialVersionUID = 1L;             /**      * @see HttpServlet#HttpServlet()      */     public HttpSessionListenerServlet() {         super();     }   /**    * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)    */   protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {     LOGGER.info("Entered into doGet(--) of HttpSessionListenerServlet class... ");              response.setContentType("text/html");               PrintWriter out = response.getWriter();     // setting “dog” attribute in request object         Dog dog = new Dog( getServletContext().getInitParameter("contextParam"));           out.print("My Dog's first name is : "+ dog.getName());     HttpSession session = request.getSession();     session.setAttribute("dog", dog);         out.print("<br/>");     out.print("<br/>");     Dog dogAttribute = (Dog)session.getAttribute("dog");     out.print("My Dog's second name is : "+ dogAttribute.getName());     out.print("<br/>");     out.print("<br/>");     dog.setName("Bubby is third pet name...");     // replacing “dog” attribute in request object     session.setAttribute("dog", dog);     // remove “dog” attribute from request object.     Dog dogAttribute2 = (Dog)session.getAttribute("dog");       out.print("My Dog's third name is : "+ dogAttribute2.getName());     session.removeAttribute("dog");     session.invalidate();   }   /**    * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)    */   protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {     LOGGER.info("Entered into doPost(--) of HttpSessionListenerServlet class... ");              doGet(request, response);   } }

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Beer title here</title> </head> <body> <form action="HttpSessionListenerServlet" method="post"> <input type="submit" value="Click here to continue..."> </form> </body> </html>

#By default enabling Console appender # Root logger option log4j.rootLogger=INFO, stdout # Redirect log messages to console log4j.appender.stdout=org.apache.log4j.ConsoleAppender log4j.appender.stdout.Target=System.out log4j.appender.stdout.layout=org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern=%-5p [%c]:%L -->> %m%n # Redirect log messages to a log file #log4j.appender.file=org.apache.log4j.RollingFileAppender #log4j.appender.file.File=C:\\servlet-application.log #log4j.appender.file.MaxFileSize=5MB #log4j.appender.file.MaxBackupIndex=10 #log4j.appender.file.layout=org.apache.log4j.PatternLayout #log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <artifactId>HttpSessionAttributeListener</artifactId> <version>1.0</version> <packaging>war</packaging> <properties> <log4j.version>1.2.16</log4j.version> <java.version>1.8</java.version> </properties> <build> <plugins> <plugin> <artifactId>maven-compiler-plugin</artifactId> <version>3.3</version> <configuration> <source>${java.version}</source> <target>${java.version}</target> </configuration> </plugin> <plugin> <artifactId>maven-war-plugin</artifactId> <version>2.6</version> <configuration> <warSourceDirectory>WebContent</warSourceDirectory> <failOnMissingWebXml>false</failOnMissingWebXml> </configuration> </plugin> </plugins> </build> <dependencies> <dependency> <groupId>javax.servlet</groupId> <artifactId>servlet-api</artifactId> <version>3.0-alpha-1</version> </dependency> <dependency> <groupId>commons-fileupload</groupId> <artifactId>commons-fileupload</artifactId> <version>1.3.1</version> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>${log4j.version}</version> </dependency> <dependency> <groupId>javax.servlet.jsp</groupId> <artifactId>jsp-api</artifactId> <version>2.0</version> </dependency> <dependency> <groupId>jstl</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency> <dependency> <groupId>taglibs</groupId> <artifactId>standard</artifactId> <version>1.1.2</version> </dependency> </dependencies> <groupId>com.cv.servlet.session.listener</groupId> </project>

<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" version="3.1"> <context-param> <param-name>contextParam</param-name> <param-value>JokeyIsTheFirstPetName</param-value> </context-param> <servlet> <servlet-name>HttpSessionListenerServlet</servlet-name> <servlet-class>com.cv.servlet.session.listener.HttpSessionListenerServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>HttpSessionListenerServlet</servlet-name> <url-pattern>/HttpSessionListenerServlet</url-pattern> </servlet-mapping> <listener> <listener-class>com.cv.servlet.session.listener.HttpSessionAttributeListenerImpl</listener-class> </listener> <welcome-file-list> <welcome-file>input.html</welcome-file> </welcome-file-list> </web-app>