启动tocat时，就运行程序里的某个方法

配置web.xml

<listener>
  <listener-class>com.function.SysContextListener </listener-class>
</listener>

java代码：

SysContextListener.javapackage com.function;

import java.util.Timer;//定时器类  
import javax.servlet.ServletContextEvent;  
import javax.servlet.ServletContextListener;  
public class SysContextListener implements ServletContextListener  
{  
  private Timer timer = null;  
  public void contextInitialized(ServletContextEvent event)  
  {//在这里初始化监听器，在tomcat启动的时候监听器启动，可以在这里实现定时器功能  
      timer = new Timer(true);  
      System.out.println("启动成功");
      event.getServletContext().log("定时器已启动--------------------------------------------------");//添加日志，可在tomcat日志中查看到  
  //   timer.schedule(new exportHistoryBean(event.getServletContext(),DealDate.getTime()),0,5*1000);//调用exportHistoryBean，0表示任务无延迟，5*1000表示每隔5秒执行任务，60*60*1000表示一个小时。  
      event.getServletContext().log("已经添加任务--------------------------------------------------");  
  }  
  public void contextDestroyed(ServletContextEvent event)  
  {//在这里关闭监听器，所以在这里销毁定时器。  
      timer.cancel();  
      event.getServletContext().log("定时器销毁--------------------------------------------------");  
  } 

}   

exportHistoryBean.javapackage com.function; 

import java.util.Calendar;
import java.util.TimerTask;
import javax.servlet.ServletContext;
 public class exportHistoryBean extends TimerTask  
 {  
   private static final int C_SCHEDULE_HOUR = 0;  
   private static boolean isRunning = false;  
   private ServletContext context = null;   
   public exportHistoryBean(ServletContext context)  
   {  
       this.context = context;   
   }  
    
   public void run()  
   {  
     Calendar c = Calendar.getInstance();  
     //if(!isRunning)  
    // {  
      // if(C_SCHEDULE_HOUR == c.get(Calendar.HOUR_OF_DAY))  
      // {  
         isRunning = true;  
         context.log("开始执行指定任务--------------------------------------------------");  
         int day = Calendar.getInstance().get(Calendar.DAY_OF_MONTH);
         new WebServiceBean().doWork();//这里就是调用自己的方法了
         isRunning = false;  
         context.log("指定任务执行结束--------------------------------------------------");  
     //  }  
      // else  
      // {  
       //  context.log("上一次任务执行还未结束");  
     //  }  
    // }  
   }  
 }