标签：
Servlet Life Cycle
http://docs.oracle.com/javaee/5/tutorial/doc/bnafi.html
Servlet Filters and Event Listeners
http://docs.oracle.com/cd/B14099_19/web.1012/b14017/filters.htm
在web.xml 中出现的先后顺序
① listener
② filter
③ servlet
原因是：
监听器有六种监听，可以监听上下文属性变化，上下文初始化，request初始化（这些先于servlet），还可以监听request的session创建属性变化和销毁等
而过滤器就好比在servlet之前加基层过滤网
项目实验：
─src └───main ├───java │ └───cn │ └───zno │ │ TestServlet.java │ │ │ └───listner │ My1ServletContextListener.java │ My2ServletContextAttributeListener.java │ My3HttpSessionListener.java │ My4HttpSessionAttributeListner.java │ My5ServletRequestListner.java │ My6ServletRequestAttributeListner.java │ ├───resources └───webapp │ index.jsp │ └───WEB-INF web.xml
// 添加一些上下文属性
18:09:55,430 INFO [stdout] (ServerService Thread Pool -- 59) 2.1 18:09:55,436 INFO [stdout] (ServerService Thread Pool -- 59) cn.zno.listner.My2ServletContextAttributeListener@355255d7 18:09:55,437 INFO [stdout] (ServerService Thread Pool -- 59) org.apache.jasper.Constants.CODE_SOURCE_ATTRIBUTE_NAME 18:09:55,438 INFO [stdout] (ServerService Thread Pool -- 59) org.apache.jasper.JSP_TAG_LIBRARIES 18:09:55,438 INFO [stdout] (ServerService Thread Pool -- 59) org.apache.tomcat.InstanceManager 18:09:55,438 INFO [stdout] (ServerService Thread Pool -- 59) javax.faces.validator.beanValidator.ValidatorFactory 18:09:55,439 INFO [stdout] (ServerService Thread Pool -- 59) org.apache.jasper.JSP_PROPERTY_GROUPS 18:09:55,439 INFO [stdout] (ServerService Thread Pool -- 59) org.jboss.as.jsf.FACES_ANNOTATIONS 18:09:55,439 INFO [stdout] (ServerService Thread Pool -- 59) io.undertow.websockets.jsr.WebSocketDeploymentInfo 18:09:55,439 INFO [stdout] (ServerService Thread Pool -- 59) org.apache.jasper.Constants.PERMISSION_COLLECTION_ATTRIBUTE_NAME 18:09:55,440 INFO [stdout] (ServerService Thread Pool -- 59) javax.websocket.server.ServerContainer 18:09:55,440 INFO [stdout] (ServerService Thread Pool -- 59) com.sun.faces.AnnotatedClasses 18:09:55,440 INFO [stdout] (ServerService Thread Pool -- 59) org.apache.jasper.SERVLET_VERSION // 添加上下文属性 18:09:55,443 INFO [stdout] (ServerService Thread Pool -- 59) 2.1 18:09:55,443 INFO [stdout] (ServerService Thread Pool -- 59) cn.zno.listner.My2ServletContextAttributeListener@355255d7 18:09:55,443 INFO [stdout] (ServerService Thread Pool -- 59) javax.servlet.context.tempdir // 初始化上下文 18:09:55,444 INFO [stdout] (ServerService Thread Pool -- 59) 1.1 // 添加上下文属性 18:09:55,485 INFO [stdout] (ServerService Thread Pool -- 59) 2.1 18:09:55,486 INFO [stdout] (ServerService Thread Pool -- 59) cn.zno.listner.My2ServletContextAttributeListener@355255d7 18:09:55,489 INFO [stdout] (ServerService Thread Pool -- 59) com.sun.faces.CONFIG_MANAGER_KEY // 添加上下文属性 18:09:55,513 INFO [stdout] (ServerService Thread Pool -- 59) 2.1 18:09:55,513 INFO [stdout] (ServerService Thread Pool -- 59) cn.zno.listner.My2ServletContextAttributeListener@355255d7 18:09:55,513 INFO [stdout] (ServerService Thread Pool -- 59) com.sun.faces.InitFacesContext // 添加上下文属性 18:09:55,542 INFO [stdout] (ServerService Thread Pool -- 59) 2.1 18:09:55,543 INFO [stdout] (ServerService Thread Pool -- 59) cn.zno.listner.My2ServletContextAttributeListener@355255d7 18:09:55,543 INFO [stdout] (ServerService Thread Pool -- 59) com.sun.faces.patternCache // 添加上下文属性 18:09:55,546 INFO [stdout] (ServerService Thread Pool -- 59) 2.1 18:09:55,547 INFO [stdout] (ServerService Thread Pool -- 59) cn.zno.listner.My2ServletContextAttributeListener@355255d7 18:09:55,547 INFO [stdout] (ServerService Thread Pool -- 59) com.sun.faces.config.WebConfiguration // 移除某个上下文属性 18:09:55,562 INFO [stdout] (ServerService Thread Pool -- 59) 2.2 18:09:55,562 INFO [stdout] (ServerService Thread Pool -- 59) 2.2 // 初始化 request 对象 18:10:17,349 INFO [stdout] (default task-2) 5.2 // 创建session 对象 18:10:21,922 INFO [stdout] (default task-2) 3.3 // 添加session 属性 18:10:21,923 INFO [stdout] (default task-2) 4.1 // 覆盖session 属性 18:10:21,924 INFO [stdout] (default task-2) 4.3 // 移除 session 属性 18:10:21,924 INFO [stdout] (default task-2) 4.2 // 添加 request 属性 18:10:21,925 INFO [stdout] (default task-2) 6.1 // 覆盖request 属性 18:10:21,925 INFO [stdout] (default task-2) 6.3 // 移除request 属性 18:10:21,926 INFO [stdout] (default task-2) 6.2 // 销毁request 对象 18:10:21,931 INFO [stdout] (default task-2) 5.1 // 销毁session（根据timeout） 18:10:32,429 INFO [stdout] (default task-3) 3.4
具体项目见：
zmvc-listeners
标签：
原文地址：http://www.cnblogs.com/zno2/p/5924651.html
