Listener Filter Servlet回溯

Listener Filter Servlet回顾
这是简单的案例，代码如下：
Listener:

import java.util.Enumeration;import javax.servlet.ServletContext;import javax.servlet.ServletContextEvent;import javax.servlet.ServletContextListener;public class MyListener implements ServletContextListener {public void contextDestroyed(ServletContextEvent sce) {System.out.println("Listener Destory");}@SuppressWarnings("unchecked")public void contextInitialized(ServletContextEvent sce) {System.out.println("Listener Initialize");ServletContext servletContext = sce.getServletContext();Enumeration<String> names = servletContext.getInitParameterNames();while (names.hasMoreElements()) {String name = names.nextElement();String value = servletContext.getInitParameter(name);System.out.println("param name : " + name + ",param value : " + value);}}}

import java.io.IOException;import java.util.Enumeration;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;public class MyFilter implements Filter {public void destroy() {System.out.println("Filter destory");}public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)throws IOException, ServletException {chain.doFilter(request, response);}@SuppressWarnings("unchecked")public void init(FilterConfig filterConfig) throws ServletException {System.out.println("Filter init");Enumeration<String> names = filterConfig.getInitParameterNames();while (names.hasMoreElements()) {String name = names.nextElement();String value = filterConfig.getInitParameter(name);System.out.println("param name : " + name + ",param value : " + value);}}}

import java.io.IOException;import java.util.Enumeration;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;@SuppressWarnings("serial")public class MyServlet extends HttpServlet{@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException,IOException {doPost(req, resp);}@SuppressWarnings("unchecked")@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {Enumeration<String> names=this.getInitParameterNames();while(names.hasMoreElements()){String name=names.nextElement();String value=this.getInitParameter(name);System.out.println("param name : " + name + ",param value : " + value);}}}

<?xml version="1.0" encoding="UTF-8"?><web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">  <context-param>      <param-name>servlet context param</param-name>      <param-value>servlet容器值</param-value>  </context-param>    <filter>     <filter-name>myFilter</filter-name>     <filter-class>MyFilter</filter-class>     <init-param>        <param-name>filter param</param-name>        <param-value>过滤器值</param-value>     </init-param>  </filter>    <filter-mapping>      <filter-name>myFilter</filter-name>      <url-pattern>/*</url-pattern>  </filter-mapping>  <servlet>     <servlet-name>myServlet</servlet-name>     <servlet-class>MyServlet</servlet-class>     <init-param>        <param-name>servlet param</param-name>        <param-value>servlet初始值</param-value>     </init-param>  </servlet>  <servlet-mapping>    <servlet-name>myServlet</servlet-name>    <url-pattern>/myServlet</url-pattern>  </servlet-mapping>    <listener>  <listener-class>MyListener</listener-class>  </listener></web-app>