监听定时器

web.xml配置监听定时器代码======================================================
<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.5"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

<display-name>Name</display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
   
   
   
    <!-- Spring ApplicationContext配置文件的路径可使用*通配符，多个路径用*,号分隔此参数用于后面的Spring-Context loader -->

<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/classes/spring/applicationContext.xml</param-value>
</context-param>

<!-- 全局变量-->
<context-param>
<param-name>appValue</param-name>
<param-value>false</param-value>
</context-param>

    <!--配置过滤器-->
    <filter>
        <filter-name>ActionFilter</filter-name>
<!--过滤类文件路径-->
        <filter-class>com.xx.ActionFilter</filter-class>       
        <init-param>
            <param-name>xx</param-name>
            <param-value>true</param-value>           
        </init-param>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>           
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>ActionFilter</filter-name>
        <url-pattern>/*</url-pattern>       
    </filter-mapping>

    <filter>
        <filter-name>struts2</filter-name>
        <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
    </filter>   

    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
       
    </filter-mapping>
    <!--加载spring配置文件applicationContext.xml-->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>   
    <!--项目启动 开启监听对应的类文件-->
     <listener>
        <listener-class>taskListener</listener-class>
    </listener>
</web-app>

JSP文件代码====================================================================

//ajax操作
$(function() {
$("#toSynchronize").click(function(){
//var activity_no = $("#activity_no").val();
$.post("${path}/xx/xx_messageMethod.do",
//{ "activity_no":"activity_no"},
function(data){
  if(data=="ex"){
     alert("可以进行操作！");
  }else{
    alert(今天已经操作过一次，请明天再警醒操作！);
  }
}
)
});

});

<input type="button" name="toSynchronize" id="toSynchronize" value="一天只可操作一次"/>


ACTION接收AJAX信息============================================================
//返回提示信息，是否可进行操作
public String messageMethod(){
     request=ServletActionContext.getRequest();
     //当天是否还可以进行操作状态false:可以操作true：不可以操作
     //全局是否存在变量toSynchronizeType
     String toSynchronizeType=(String) ServletActionContext.getServletContext().getAttribute("toSynchronizeType");
     //从配置文件web.xml中取得初始全局变量toSynchronizeType
     String initToSynchronizeType=ServletActionContext.getServletContext().getInitParameter("toSynchronizeType");
     boolean blean=false;
try{
  if(toSynchronizeType!=null && !"".equals(toSynchronizeType)){
    //如果全局中存在toSynchronizeType全局变量，并且值为false是 返回可操作提示信息
    //同时设定变量值为true
    if(toSynchronizeType.equals("false")){
ServletActionContext.getServletContext().setAttribute("toSynchronizeType", "true");
//要进行的操作编码省略
ServletActionContext.getResponse().getWriter().print("ex");
    //如果为true，返回不可操作信息
    }else{
ServletActionContext.getResponse().getWriter().print("notEx");
    }
    //如果全局中不存在toSynchronizeType变量，则判断初始全局变量，如果为falae，则返回可操作提示信息
    //同时给定全局变量为true
  }else{
    if(initToSynchronizeType.equals("false")){
ServletActionContext.getServletContext().setAttribute("toSynchronizeType", "true");
//要进行的操作编码省略
ServletActionContext.getResponse().getWriter().print("ex");
     }
   }
}catch(Exception e){
      blean=false;
      e.printStackTrace();
  }
    request.setAttribute("blean", Boolean.toString(blean));
    return null;
}



监听定时器类=========================================================================
import java.util.Timer;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
/**
* 监听定时器
      
* 实现ServletContextListener
*
*/
public class taskListener implements ServletContextListener{

public void contextDestroyed(ServletContextEvent event) {
}

public void contextInitialized(ServletContextEvent contextEvent) {
          //获得ServletContext
  ServletContext servletContext = contextEvent.getServletContext();
  //取得web.xml文件中的初始变量值
  String toSynchronizeType=servletContext.getInitParameter("toSynchronizeType");
  //声明定时器
  Timer timer = new Timer();
  //每小时执行一次任务
          timer.schedule(new task(servletContext),0,3600*1000);
}

}



定时任务类===========================================================================
import java.util.Calendar;
import java.util.TimerTask;
import javax.servlet.ServletContext;
/**
* 定时器任务类
*
*
*/
public class task extends TimerTask {

ServletContext servletContext=null;

private static final int C_SCHEDULE_HOUR = 0;

//构造函数
public task(ServletContext servletContext){

   this.servletContext=servletContext;
}

    public void run() {
        Calendar cal = Calendar.getInstance();
        //每天零点执行更新
        if (C_SCHEDULE_HOUR == cal.get(Calendar.HOUR_OF_DAY))
        {
            try
            {
            System.err.println("定时任务开始==========================");
            //取得全局变量
            String toSynchronize=(String) servletContext.getAttribute("toSynchronizeType");
           
            System.out.println("现是否已經作状态="+toSynchronize);
           
            if(toSynchronize!=null && !toSynchronize.equals("")){
           
                System.out.println("正在重置状态=====================");
           
                if(toSynchronize.equals("true")){
           
            servletContext.setAttribute("toSynchronizeType", "false");

                    System.err.println("状态已经重置，可以进行操作了.........");
    }
           

            }
              
            } catch (Exception e)
            {
                e.printStackTrace();
            }
        }
    }
}