Servlet Life Cycle

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