<%-- 网站: <a href="http://www.crazyit.org">疯狂Java联盟</a> author yeeku.H.lee kongyeeku@163.com version 1.0 Copyright (C), 2001-2016, yeeku.H.Lee This program is protected by copyright laws. Program Name: Date: --%> <%@ page contentType="text/html; charset=GBK" language="java" errorPage="" %> <%@ page import="java.sql.*" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title> 测试ServletContextListener </title> <meta name="website" content="http://www.crazyit.org" /> </head> <body> 下面是直接从application中取出数据库连接，<br/> 并执行查询后的结果<br/> <% Connection conn = (Connection)application.getAttribute("conn"); // 创建Statement对象 Statement stmt = conn.createStatement(); // 执行查询 ResultSet rs = stmt.executeQuery("select * from news_inf"); %> <table bgcolor="#9999dd" border="1" width="300"> <% // 遍历结果集 while(rs.next()) { %> <tr> <td><%=rs.getString(1)%></td> <td><%=rs.getString(2)%></td> </tr> <% } %> <table> </body> </html>
<%-- 网站: <a href="http://www.crazyit.org">疯狂Java联盟</a> author yeeku.H.lee kongyeeku@163.com version 1.0 Copyright (C), 2001-2016, yeeku.H.Lee This program is protected by copyright laws. Program Name: Date: --%> <%@ page contentType="text/html; charset=GBK" language="java" errorPage="" %> <%@ page import="java.util.*" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title> 用户在线信息 </title> <meta name="website" content="http://www.crazyit.org" /> </head> <body> 在线用户： <table width="400" border="1"> <% Map<String , String> online = (Map<String , String>)application .getAttribute("online"); for (String sessionId : online.keySet()) {%> <tr> <td><%=sessionId%> <td><%=online.get(sessionId)%> </tr> <%}%> </body> </html>
<?xml version="1.0" encoding="GBK"?> <!-- 定义生成文件的project根元素，默认的target为空 --> <project name="web" basedir="." default=""> <!-- 定义三个简单属性 --> <property name="src" value="src"/> <property name="classes" value="classes"/> <!-- 定义一组文件和目录集 --> <path id="classpath"> <fileset dir="lib"> <include name="**/*.jar"/> </fileset> <pathelement path="${classes}"/> </path> <!-- 定义compile target，用于编译Java源文件 --> <target name="compile" description="编译Java源文件"> <!-- 先删除classes属性所代表的文件夹 --> <delete dir="${classes}"/> <!-- 创建classes属性所代表的文件夹 --> <mkdir dir="${classes}"/> <copy todir="${classes}"> <fileset dir="${src}"> <exclude name="**/*.java"/> </fileset> </copy> <!-- 编译Java文件，编译后的class文件放到classes属性所代表的文件夹内 --> <javac destdir="${classes}" debug="true" includeantruntime="yes" deprecation="false" optimize="false" failonerror="true"> <!-- 指定需要编译的Java文件所在的位置 --> <src path="${src}"/> <!-- 指定编译Java文件所需要第三方类库所在的位置 --> <classpath refid="classpath"/> </javac> </target> </project>
<?xml version="1.0" encoding="GBK"?> <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" version="3.1"> <!-- 配置第一个参数：driver --> <context-param> <param-name>driver</param-name> <param-value>com.mysql.jdbc.Driver</param-value> </context-param> <!-- 配置第二个参数：url --> <context-param> <param-name>url</param-name> <param-value>jdbc:mysql://localhost:3306/javaee</param-value> </context-param> <!-- 配置第三个参数：user --> <context-param> <param-name>user</param-name> <param-value>root</param-value> </context-param> <!-- 配置第四个参数：pass --> <context-param> <param-name>pass</param-name> <param-value>32147</param-value> </context-param> <listener> <!-- 指定Listener的实现类 --> <listener-class>lee.GetConnListener</listener-class> </listener> </web-app>
package lee; import javax.servlet.*; import javax.servlet.annotation.*;/** * Description: * <br/>网站: <a href="http://www.crazyit.org">疯狂Java联盟</a> * <br/>Copyright (C), 2001-2016, Yeeku.H.Lee * <br/>This program is protected by copyright laws. * <br/>Program Name: * <br/>Date: * @author Yeeku.H.Lee kongyeeku@163.com * @version 1.0 */ @WebListener public class MyServletContextAttributeListener implements ServletContextAttributeListener { // 当程序向application范围添加属性时触发该方法 public void attributeAdded(ServletContextAttributeEvent event) { ServletContext application = event.getServletContext(); // 获取添加的属性名和属性值 String name = event.getName(); Object value = event.getValue(); System.out.println(application + "范围内添加了名为" + name + "，值为" + value + "的属性!"); } // 当程序从application范围删除属性时触发该方法 public void attributeRemoved(ServletContextAttributeEvent event) { ServletContext application = event.getServletContext(); // 获取被删除的属性名和属性值 String name = event.getName(); Object value = event.getValue(); System.out.println(application + "范围内名为" + name + "，值为" + value + "的属性被删除了!"); } // 当application范围的属性被替换时触发该方法 public void attributeReplaced(ServletContextAttributeEvent event) { ServletContext application = event.getServletContext(); // 获取被替换的属性名和属性值 String name = event.getName(); Object value = event.getValue(); System.out.println(application + "范围内名为" + name + "，值为" + value + "的属性被替换了!"); } }
package lee; import javax.servlet.*; import javax.servlet.annotation.*; import javax.servlet.http.*;import java.util.*;/** * Description: * <br/>网站: <a href="http://www.crazyit.org">疯狂Java联盟</a> * <br/>Copyright (C), 2001-2016, Yeeku.H.Lee * <br/>This program is protected by copyright laws. * <br/>Program Name: * <br/>Date: * @author Yeeku.H.Lee kongyeeku@163.com * @version 1.0 */ @WebListener public class OnlineListener implements HttpSessionListener { // 当用户与服务器之间开始session时触发该方法 public void sessionCreated(HttpSessionEvent se) { HttpSession session = se.getSession(); ServletContext application = session.getServletContext(); // 获取session ID String sessionId = session.getId(); // 如果是一次新的会话 if (session.isNew()) { String user = (String)session.getAttribute("user"); // 未登录用户当游客处理 user = (user == null) ? "游客" : user; Map<String , String> online = (Map<String , String>) application.getAttribute("online"); if (online == null) { online = new Hashtable<String , String>(); } // 将用户在线信息放入Map中 online.put(sessionId , user); application.setAttribute("online" , online); } } // 当用户与服务器之间session断开时触发该方法 public void sessionDestroyed(HttpSessionEvent se) { HttpSession session = se.getSession(); ServletContext application = session.getServletContext(); String sessionId = session.getId(); Map<String , String> online = (Map<String , String>) application.getAttribute("online"); if (online != null) { // 删除该用户的在线信息 online.remove(sessionId); } application.setAttribute("online" , online); } }
package lee; import javax.servlet.*; import javax.servlet.http.*; import javax.servlet.annotation.*; /** * Description: * <br/>网站: <a href="http://www.crazyit.org">疯狂Java联盟</a> * <br/>Copyright (C), 2001-2016, Yeeku.H.Lee * <br/>This program is protected by copyright laws. * <br/>Program Name: * <br/>Date: * @author Yeeku.H.Lee kongyeeku@163.com * @version 1.0 */ @WebListener public class RequestListener implements ServletRequestListener , ServletRequestAttributeListener { // 当用户请求到达、被初始化时触发该方法 public void requestInitialized(ServletRequestEvent sre) { HttpServletRequest request = (HttpServletRequest)sre.getServletRequest(); System.out.println("----发向" + request.getRequestURI() + "请求被初始化----"); } // 当用户请求结束、被销毁时触发该方法 public void requestDestroyed(ServletRequestEvent sre) { HttpServletRequest request = (HttpServletRequest)sre.getServletRequest(); System.out.println("----发向" + request.getRequestURI() + "请求被销毁----"); } // 当程序向request范围添加属性时触发该方法 public void attributeAdded(ServletRequestAttributeEvent event) { ServletRequest request = event.getServletRequest(); // 获取添加的属性名和属性值 String name = event.getName(); Object value = event.getValue(); System.out.println(request + "范围内添加了名为" + name + "，值为" + value + "的属性!"); } // 当程序从request范围删除属性时触发该方法 public void attributeRemoved(ServletRequestAttributeEvent event) { ServletRequest request = event.getServletRequest(); // 获取被删除的属性名和属性值 String name = event.getName(); Object value = event.getValue(); System.out.println(request + "范围内名为" + name + "，值为" + value + "的属性被删除了!"); } // 当request范围的属性被替换时触发该方法 public void attributeReplaced(ServletRequestAttributeEvent event) { ServletRequest request = event.getServletRequest(); // 获取被替换的属性名和属性值 String name = event.getName(); Object value = event.getValue(); System.out.println(request + "范围内名为" + name + "，值为" + value + "的属性被替换了!"); } }
package lee; import java.sql.*; import javax.servlet.*; import javax.servlet.annotation.*; /** * Description: * <br/>网站: <a href="http://www.crazyit.org">疯狂Java联盟</a> * <br/>Copyright (C), 2001-2016, Yeeku.H.Lee * <br/>This program is protected by copyright laws. * <br/>Program Name: * <br/>Date: * @author Yeeku.H.Lee kongyeeku@163.com * @version 1.0 */ @WebListener public class GetConnListener implements ServletContextListener { // 应该启动时，该方法被调用。 public void contextInitialized(ServletContextEvent sce) { try { // 取得该应用的ServletContext实例 ServletContext application = sce.getServletContext(); // 从配置参数中获取驱动 String driver = application.getInitParameter("driver"); // 从配置参数中获取数据库url String url = application.getInitParameter("url"); // 从配置参数中获取用户名 String user = application.getInitParameter("user"); // 从配置参数中获取密码 String pass = application.getInitParameter("pass"); // 注册驱动 Class.forName(driver); // 获取数据库连接 Connection conn = DriverManager.getConnection(url , user , pass); // 将数据库连接设置成application范围内的属性 application.setAttribute("conn" , conn); } catch (Exception ex) { System.out.println("Listener中获取数据库连接出现异常" + ex.getMessage()); } } // 应该关闭时，该方法被调用。 public void contextDestroyed(ServletContextEvent sce) { // 取得该应用的ServletContext实例 ServletContext application = sce.getServletContext(); Connection conn = (Connection)application.getAttribute("conn"); // 关闭数据库连接 if (conn != null) { try { conn.close(); } catch (SQLException ex) { ex.printStackTrace(); } } } }