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wst0350:
点赞,有空深入讲解下原理
Servlet、Filter 和 Listener 调用顺序、生命周期的实验分析 -
tuspark:
Eclipse中高亮设置内容还有很多细节选项可以设置的,可以看 ...
Eclipse 设置匹配代码高亮 -
xichao1929:
这个时候,怎么启动发布的项目呢?????
JBoss设置为Windows服务 -
xiaozi7:
非常感谢,楼主的英语水平不一般那
WebSphere MQ Version 7 发布订阅相关配置 -
qtlkw:
slave没玩过
Hudson: java.lang.OutOfMemoryError: Java heap space error
通过实验来验证Servlet、Filter和Listener的调用顺序、生命周期。
1、示例项目
目录结构:
web.xml
MyServletContextListener类:
MyServletRequestListener类:
ResponseFilter类:
LogFilter类:
HelloServlet类:
EarlyServlet类:
2、测试操作
1、启动tomcat服务
2、访问http://10.130.29.198:8080/test/ (访问index.html)
3、访问http://10.130.29.198:8080/test/hello
4、访问http://10.130.29.198:8080/test/early
5、停止tomcat服务
3、Log输出
(根据输出的时间,人为的把日志分割开来,便于观察)
1、启动tomcat服务
2013-03-28 18:14:08,954 INFO - [MyServletContextListener - contextInitialized] Servlet context initialized.
2013-03-28 18:14:08,983 INFO - [LogFilter - init] Log Filter initialized.
2013-03-28 18:14:08,984 INFO - [ResponseFilter - init] Response Filter initialized.
2013-03-28 18:14:08,991 DEBUG - [EarlyServlet - init] Early Servlet initialized.
2、访问http://10.130.29.198:8080/test/ (访问index.html)
2013-03-28 18:14:18,946 INFO - [MyServletRequestListener - requestInitialized] Servlet request initialized.
2013-03-28 18:14:18,957 INFO - [LogFilter - doFilter] Intercept Url=/test/
2013-03-28 18:14:18,962 INFO - [LogFilter - doFilter] 10.130.29.198: time used :4
2013-03-28 18:14:18,963 INFO - [MyServletRequestListener - requestDestroyed] Servlet request destroyed.
3、访问http://10.130.29.198:8080/test/hello
2013-03-28 18:14:34,713 INFO - [MyServletRequestListener - requestInitialized] Servlet request initialized.
2013-03-28 18:14:34,714 DEBUG - [HelloServlet - init] Hello Servlet initialized.
2013-03-28 18:14:34,716 INFO - [LogFilter - doFilter] Intercept Url=/test/hello
2013-03-28 18:14:34,717 DEBUG - [HelloServlet - doGet] Do Get Method.
2013-03-28 18:14:34,720 INFO - [LogFilter - doFilter] 10.130.29.198: time used :3
2013-03-28 18:14:34,721 INFO - [MyServletRequestListener - requestDestroyed] Servlet request destroyed.
4、访问http://10.130.29.198:8080/test/early
2013-03-28 18:14:42,124 INFO - [MyServletRequestListener - requestInitialized] Servlet request initialized.
2013-03-28 18:14:42,127 INFO - [LogFilter - doFilter] Intercept Url=/test/early
2013-03-28 18:14:42,128 DEBUG - [EarlyServlet - doGet] Do Get Method.
2013-03-28 18:14:42,129 INFO - [LogFilter - doFilter] 10.130.29.198: time used :1
2013-03-28 18:14:42,130 INFO - [MyServletRequestListener - requestDestroyed] Servlet request destroyed.
5、停止tomcat服务
2013-03-28 18:14:49,723 DEBUG - [EarlyServlet - destroy] Early Servlet destroyed.
2013-03-28 18:14:49,724 DEBUG - [HelloServlet - destroy] Hello Servlet destroyed.
2013-03-28 18:14:49,724 INFO - [LogFilter - destroy] Log Filter destroyed.
2013-03-28 18:14:49,726 INFO - [ResponseFilter - destroy] Response Filter destroyed.
2013-03-28 18:14:49,727 INFO - [MyServletContextListener - contextDestroyed] Servlet context destroyed.
4、分析
1、在Tomcat(Servlet容器)启动时,Listener和 ServletContext 最先初始化。因为最先输出的日志是:
2013-03-28 18:14:08,954 INFO - [MyServletContextListener - contextInitialized] Servlet context initialized.
2、Filter在Tomcat(Servlet容器)启动时初始化。
2013-03-28 18:14:08,983 INFO - [LogFilter - init] Log Filter initialized.
2013-03-28 18:14:08,984 INFO - [ResponseFilter - init] Response Filter initialized.
3、如果某个Servlet配置了 <load-on-startup >1 </load-on-startup >,该Servlet也是在Tomcat(Servlet容器)启动时初始化。例如 EarlyServlet:
2013-03-28 18:14:08,991 DEBUG - [EarlyServlet - init] Early Servlet initialized.
4、每次请求, Request都会被初始化,响应请求后,请求被销毁:
2013-03-28 18:14:18,946 INFO - [MyServletRequestListener - requestInitialized] Servlet request initialized.
......
2013-03-28 18:14:18,963 INFO - [MyServletRequestListener - requestDestroyed] Servlet request destroyed.
5、Filter在请求执行前后,都能做一些处理。
(1)请求执行前:2013-03-28 18:14:34,716 INFO - [LogFilter - doFilter] Intercept Url=/test/hello
(2)执行请求:2013-03-28 18:14:34,717 DEBUG - [HelloServlet - doGet] Do Get Method.
(3)请求执行后:2013-03-28 18:14:34,720 INFO - [LogFilter - doFilter] 10.130.29.198: time used :3
6、如果Servlet没有配置<load-on-startup >1 </load-on-startup >,该Servlet不会在Tomcat启动时初始化,而是在请求到来时初始化。例如 HelloServlet:
2013-03-28 18:14:34,714 DEBUG - [HelloServlet - init] Hello Servlet initialized.
7、Servlet初始化后,将不会随着请求的结束而注销。HelloServlet 初始化,当请求结束了,HelloServlet 的 destroy() 没有被调用。
8、关闭Tomcat时,Servlet、Filter、Listener依次被注销。
1、示例项目
目录结构:
web.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd"> <web-app> <listener> <listener-class>edu.shao.webapp.sample.listener.MyServletRequestListener</listener-class> </listener> <listener> <listener-class>edu.shao.webapp.sample.listener.MyServletContextListener</listener-class> </listener> <filter> <filter-name>ResponseFilter</filter-name> <filter-class>edu.shao.webapp.sample.filter.ResponseFilter</filter-class> </filter> <filter-mapping> <filter-name>ResponseFilter</filter-name> <servlet-name>hello_world</servlet-name> </filter-mapping> <filter> <filter-name>LogFilter</filter-name> <filter-class>edu.shao.webapp.sample.filter.LogFilter</filter-class> </filter> <filter-mapping> <filter-name>LogFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <servlet> <servlet-name>hello_world</servlet-name> <servlet-class>edu.shao.webapp.sample.HelloServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>hello_world</servlet-name> <url-pattern>/hello</url-pattern> </servlet-mapping> <servlet> <servlet-name>early_servlet</servlet-name> <servlet-class>edu.shao.webapp.sample.EarlyServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>early_servlet</servlet-name> <url-pattern>/early</url-pattern> </servlet-mapping> </web-app>
MyServletContextListener类:
public class MyServletContextListener implements ServletContextListener { public static Logger logger=LogManager.getLogger(MyServletContextListener.class); @Override public void contextInitialized(ServletContextEvent sce) { logger.info("Servlet context initialized."); } @Override public void contextDestroyed(ServletContextEvent sce) { logger.info("Servlet context destroyed."); } }
MyServletRequestListener类:
public class MyServletRequestListener implements ServletRequestListener { public static Logger logger=LogManager.getLogger(MyServletRequestListener.class); @Override public void requestDestroyed(ServletRequestEvent sre) { logger.info("Servlet request destroyed."); } @Override public void requestInitialized(ServletRequestEvent sre) { logger.info("Servlet request initialized."); } }
ResponseFilter类:
public class ResponseFilter implements Filter { public static Logger logger=LogManager.getLogger(ResponseFilter.class); @Override public void init(FilterConfig arg0) throws ServletException { logger.info("Response Filter initialized."); } @Override public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException { chain.doFilter(req, res); res.getWriter().write("--@2013 Mr.Shao"); } @Override public void destroy() { logger.info("Response Filter destroyed."); } }
LogFilter类:
public class LogFilter implements Filter { public static Logger logger=LogManager.getLogger(LogFilter.class); @Override public void init(FilterConfig filterConfig) throws ServletException { logger.info("Log Filter initialized."); } @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { HttpServletRequest httpServletRequest = (HttpServletRequest)request; logger.info("Intercept Url="+httpServletRequest.getRequestURI()); long start=System.currentTimeMillis(); chain.doFilter(request, response); long end=System.currentTimeMillis(); logger.info(request.getRemoteAddr()+": time used :"+(end-start)); } @Override public void destroy() { logger.info("Log Filter destroyed."); } }
HelloServlet类:
public class HelloServlet extends HttpServlet { public static Logger logger=LogManager.getLogger(HelloServlet.class); @Override public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { logger.debug("Do Get Method."); resp.getWriter().print("Hello World"); } public void init() throws ServletException { logger.debug("Hello Servlet initialized."); } public void destroy() { logger.debug("Hello Servlet destroyed."); } }
EarlyServlet类:
public class EarlyServlet extends HttpServlet { public static Logger logger=LogManager.getLogger(EarlyServlet.class); @Override public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { logger.debug("Do Get Method."); resp.getWriter().print("This message is created in EarlyServlet"); } public void init() throws ServletException { logger.debug("Early Servlet initialized."); } public void destroy() { logger.debug("Early Servlet destroyed."); } }
2、测试操作
1、启动tomcat服务
2、访问http://10.130.29.198:8080/test/ (访问index.html)
3、访问http://10.130.29.198:8080/test/hello
4、访问http://10.130.29.198:8080/test/early
5、停止tomcat服务
3、Log输出
(根据输出的时间,人为的把日志分割开来,便于观察)
1、启动tomcat服务
2013-03-28 18:14:08,954 INFO - [MyServletContextListener - contextInitialized] Servlet context initialized.
2013-03-28 18:14:08,983 INFO - [LogFilter - init] Log Filter initialized.
2013-03-28 18:14:08,984 INFO - [ResponseFilter - init] Response Filter initialized.
2013-03-28 18:14:08,991 DEBUG - [EarlyServlet - init] Early Servlet initialized.
2、访问http://10.130.29.198:8080/test/ (访问index.html)
2013-03-28 18:14:18,946 INFO - [MyServletRequestListener - requestInitialized] Servlet request initialized.
2013-03-28 18:14:18,957 INFO - [LogFilter - doFilter] Intercept Url=/test/
2013-03-28 18:14:18,962 INFO - [LogFilter - doFilter] 10.130.29.198: time used :4
2013-03-28 18:14:18,963 INFO - [MyServletRequestListener - requestDestroyed] Servlet request destroyed.
3、访问http://10.130.29.198:8080/test/hello
2013-03-28 18:14:34,713 INFO - [MyServletRequestListener - requestInitialized] Servlet request initialized.
2013-03-28 18:14:34,714 DEBUG - [HelloServlet - init] Hello Servlet initialized.
2013-03-28 18:14:34,716 INFO - [LogFilter - doFilter] Intercept Url=/test/hello
2013-03-28 18:14:34,717 DEBUG - [HelloServlet - doGet] Do Get Method.
2013-03-28 18:14:34,720 INFO - [LogFilter - doFilter] 10.130.29.198: time used :3
2013-03-28 18:14:34,721 INFO - [MyServletRequestListener - requestDestroyed] Servlet request destroyed.
4、访问http://10.130.29.198:8080/test/early
2013-03-28 18:14:42,124 INFO - [MyServletRequestListener - requestInitialized] Servlet request initialized.
2013-03-28 18:14:42,127 INFO - [LogFilter - doFilter] Intercept Url=/test/early
2013-03-28 18:14:42,128 DEBUG - [EarlyServlet - doGet] Do Get Method.
2013-03-28 18:14:42,129 INFO - [LogFilter - doFilter] 10.130.29.198: time used :1
2013-03-28 18:14:42,130 INFO - [MyServletRequestListener - requestDestroyed] Servlet request destroyed.
5、停止tomcat服务
2013-03-28 18:14:49,723 DEBUG - [EarlyServlet - destroy] Early Servlet destroyed.
2013-03-28 18:14:49,724 DEBUG - [HelloServlet - destroy] Hello Servlet destroyed.
2013-03-28 18:14:49,724 INFO - [LogFilter - destroy] Log Filter destroyed.
2013-03-28 18:14:49,726 INFO - [ResponseFilter - destroy] Response Filter destroyed.
2013-03-28 18:14:49,727 INFO - [MyServletContextListener - contextDestroyed] Servlet context destroyed.
4、分析
1、在Tomcat(Servlet容器)启动时,Listener和 ServletContext 最先初始化。因为最先输出的日志是:
2013-03-28 18:14:08,954 INFO - [MyServletContextListener - contextInitialized] Servlet context initialized.
2、Filter在Tomcat(Servlet容器)启动时初始化。
2013-03-28 18:14:08,983 INFO - [LogFilter - init] Log Filter initialized.
2013-03-28 18:14:08,984 INFO - [ResponseFilter - init] Response Filter initialized.
3、如果某个Servlet配置了 <load-on-startup >1 </load-on-startup >,该Servlet也是在Tomcat(Servlet容器)启动时初始化。例如 EarlyServlet:
2013-03-28 18:14:08,991 DEBUG - [EarlyServlet - init] Early Servlet initialized.
4、每次请求, Request都会被初始化,响应请求后,请求被销毁:
2013-03-28 18:14:18,946 INFO - [MyServletRequestListener - requestInitialized] Servlet request initialized.
......
2013-03-28 18:14:18,963 INFO - [MyServletRequestListener - requestDestroyed] Servlet request destroyed.
5、Filter在请求执行前后,都能做一些处理。
(1)请求执行前:2013-03-28 18:14:34,716 INFO - [LogFilter - doFilter] Intercept Url=/test/hello
(2)执行请求:2013-03-28 18:14:34,717 DEBUG - [HelloServlet - doGet] Do Get Method.
(3)请求执行后:2013-03-28 18:14:34,720 INFO - [LogFilter - doFilter] 10.130.29.198: time used :3
6、如果Servlet没有配置<load-on-startup >1 </load-on-startup >,该Servlet不会在Tomcat启动时初始化,而是在请求到来时初始化。例如 HelloServlet:
2013-03-28 18:14:34,714 DEBUG - [HelloServlet - init] Hello Servlet initialized.
7、Servlet初始化后,将不会随着请求的结束而注销。HelloServlet 初始化,当请求结束了,HelloServlet 的 destroy() 没有被调用。
8、关闭Tomcat时,Servlet、Filter、Listener依次被注销。
发表评论
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es使用两种方式
2018-06-28 16:26 0第一种方式: 使用TransportClient packag ... -
hbase
2018-06-25 13:50 0package cn.com.duiba.appordersy ... -
guava
2017-09-22 18:03 5721.Guava Cache的get/getIfPresent方 ... -
转:架构
2017-06-23 08:13 456架构是软件的核心和灵魂,没有好的架构的软件经过一段时间的迭代后 ... -
使用 redis 减少 秒杀库存 超卖思路
2017-06-22 23:58 554512月份重构公司社群活动产品,原来自己不是很成熟,按传统的形式 ... -
经典笔试题
2017-06-21 23:30 458public class BaseTest { pu ... -
Restful vs RPC
2017-01-23 10:54 819传统的RPC一般是基于二 ... -
自动产生随机数
2016-11-11 10:54 504/** * java生成随机数字和字母组合 ... -
commons-lang常用工具类StringEscapeUtils
2016-11-10 20:12 8271.escapeSql 提供sql转移功能,防止sql注入攻击 ... -
Java8:Lambda表达式增强版Comparator和排序
2016-10-27 10:32 2641http://www.importnew.com/15259. ... -
Java序列化几点注意事项
2016-10-26 17:02 849静态变量不属于对象,属于类,不能被序列化.还有瞬态的变量也不能 ... -
Rest vs dubbo
2016-09-15 18:10 0Rest 基于http, 大数据量和安全性可能不佳 dubbo ... -
List删除element两种方式的不同
2016-07-26 12:41 638public class DateUtilTest { ... -
Xmemcached——比spymemcached更快
2016-07-18 10:23 425Xmemcached是一个高性能的 ... -
velocity 缓存设置
2016-07-04 20:54 1017#velocity 是否开启缓存 velocity.resou ... -
Java8 Stream用法
2016-07-04 18:58 01. collect(toList()) 由stream里的值 ... -
熔断器设计模式
2016-05-22 23:14 559转载: http://www.cnblogs.com/ ... -
Date 参数
2016-04-22 21:44 518Oracle TO_CHAR parameters: The ... -
Dubbo安装部署
2016-04-18 01:16 1555Jdk-1.6.30以上版本 Tomcat-7 ... -
java read也需要加锁
2016-02-27 18:11 592今天被问到read需不需要加锁,结果没答上来。自己写了一个程序 ...
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