package com.log.service; import java.util.Enumeration; import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener; import com.util.UtilPrint; /**
* 对应慕课网 3-1，http://www.imooc.com/video/5658，
* ServletContextListener的主要用途：
* 1 定时器
* 2 获取全局属性对象(设置全局属性对象)
* 3 获取web.xml中的初始化参数
* @author Wei
* @time 2016年10月4日 下午8:38:37
*/
public class WylContextListener implements ServletContextListener { public WylContextListener() {
System.out.println("com.log.service.WylContextListener()实例化,");
} @Override
public void contextInitialized(ServletContextEvent sce) {
System.out.println("com.log.service.WylContextListener.contextInitialized()...,");
ServletContext sc = sce.getServletContext();
/**
* 设置全局变量，然后再整个应用的生命周期里都可以获取到
*/
sc.setAttribute("theGlobalPara", "我是全局的属性对象，");
Enumeration<String> initparaNames = sc.getInitParameterNames();
if (initparaNames.hasMoreElements()) {
String name = initparaNames.nextElement();
/**
* 获取web.xml中的初始化参数，
* <context-param>
* <param-name>ctxName</param-name>
* <param-value>我是ctx的值</param-value>
* </context-param>
*/
String initValue = sc.getInitParameter(name);
UtilPrint.printWithSeparatorAndClass("------name:" + name + ",initValue:" + initValue,
WylContextListener.class);
} else {
UtilPrint.printWithSeparatorAndClass("com.log.service.WylContextListener.contextInitialized()...,没有获取到初始化参数", WylContextListener.class);
}
}
@Override
public void contextDestroyed(ServletContextEvent sce) {
// TODO Auto-generated method stub
System.out.println("com.log.service.WylContextListener.contextDestroyed()...,");
} }
web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
id="WebApp_ID" version="2.5"> <!-- 配置 Struts2 的 Filter -->
<welcome-file-list> <!-- <welcome-file>index.jsp</welcome-file> 欢迎页改为MyTag.jsp -->
<welcome-file>MyTag.jsp</welcome-file>
</welcome-file-list> <listener>
<listener-class>com.log.service.WylSessionAttrbuteLister</listener-class>
</listener> <listener>
<listener-class>com.log.service.WylSessionListener</listener-class>
</listener>
<!-- ServletRequestListener -->
<listener>
<listener-class>com.log.service.WylServletRequestListener</listener-class>
</listener> <listener>
<listener-class>com.log.service.WylContextListener</listener-class>
</listener> <servlet>
<servlet-name>freemarker</servlet-name>
<servlet-class>freemarker.ext.servlet.FreemarkerServlet</servlet-class>
<!--下面的配置freemarke的ftl文件的位置 -->
<init-param>
<param-name>TemplatePath</param-name>
<param-value>/</param-value>
</init-param>
<!-- 是否和服务器（tommcat)一起启动。0为不。1为是 -->
<load-on-startup>1</load-on-startup>
</servlet> <servlet-mapping>
<servlet-name>freemarker</servlet-name>
<url-pattern>*.ftl</url-pattern>
</servlet-mapping> <servlet>
<!-- define a JspSupportServlet Object -->
<servlet-name>JspSupportServlet</servlet-name>
<servlet-class>org.apache.struts2.views.JspSupportServlet</servlet-class>
<!-- setting JspSupportServlet auto start -->
<load-on-startup>1</load-on-startup>
</servlet> <!-- <filter> <filter-name>struts2</filter-name> <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter> <filter-mapping> <filter-name>struts2</filter-name> <url-pattern>/*</url-pattern>
</filter-mapping> -->
<filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter> <filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping> <!-- 我的自定义过滤器 --> <filter>
<filter-name>wylFiler3</filter-name>
<filter-class>com.test.javaAPI.servlet.MyFilter3</filter-class>
</filter> <filter-mapping>
<filter-name>wylFiler3</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping> <filter>
<filter-name>wylFiler4</filter-name>
<filter-class>com.test.javaAPI.servlet.MyFilterXX</filter-class>
</filter> <filter-mapping>
<filter-name>wylFiler4</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping> <filter>
<filter-name>wylFiler1</filter-name>
<filter-class>com.test.javaAPI.servlet.MyFilter1</filter-class>
</filter> <filter-mapping>
<filter-name>wylFiler1</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping> <filter>
<filter-name>wylFiler2</filter-name>
<filter-class>com.test.javaAPI.servlet.MyFilter2</filter-class>
</filter> <filter-mapping>
<filter-name>wylFiler2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping> <!-- 测试servlet用的，20161004 -->
<servlet>
<servlet-name>testMy</servlet-name>
<servlet-class>com.test.javaAPI.servlet.MyServlet</servlet-class> </servlet> <servlet-mapping>
<servlet-name>testMy</servlet-name>
<url-pattern>*.xxx</url-pattern>
</servlet-mapping> <!-- 测试servlet用的，20161004 -->
<servlet>
<servlet-name>testMy2</servlet-name>
<servlet-class>com.test.javaAPI.servlet.MyServlet2</servlet-class>
<!-- 设置 web容器已启动就实例化这个servlet，servlet一旦实例化就会调用初始化方法init(),而且生命周期里只会实例化一次 -->
<load-on-startup>1</load-on-startup>
</servlet> <servlet-mapping>
<servlet-name>testMy2</servlet-name>
<url-pattern>*.yyy</url-pattern>
</servlet-mapping>
<!-- 可以通过通过监听器来获取到，当然了，需要实现ServletContextListener接口 ，
见：com.log.service.WylContextListener-->
<context-param>
<param-name>ctxName</param-name>
<param-value>我是ctx的值</param-value>
</context-param> </web-app>
如下图，已经获取到web.xml中的<context-param>标签中设置的值了，
