EJB 定时服务实现

最新推荐文章于 2016-06-30 19:48:09 发布

lhcelf

最新推荐文章于 2016-06-30 19:48:09 发布

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文章标签： ejb timer import class iterator exception

本文链接：https://blog.csdn.net/lhcelf/article/details/7284655

版权

用EJB3.0实现定时服务，并提供实现取消所有已启动的服务。

远程接口

package examples.timer.remote;
/**
 *@Project:[SayHello]
 *@Package:[examples.timer.remote]
 *@Class:[TimerService.java]
 *@author: lhc
 *@time:2012-2-19 下午12:19:04 
 *@version: 1.0.0
 *@Copy:2012 y_rich
 */
public interface TimerService 
{ 
  public void scheduleTimer(long milliseconds); 
  public boolean cancelTimer();
}

实现

package examples.timer.Intface;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Iterator;

import javax.annotation.Resource;
import javax.ejb.Remote;
import javax.ejb.SessionContext;
import javax.ejb.Stateless;
import javax.ejb.Timeout;
import javax.ejb.Timer;
import javax.persistence.EntityManager;
import javax.persistence.Query;
import examples.timer.remote.TimerService;

/**
 *@Project:[SayHello]
 *@Package:[examples.timer.Inface]
 *@Class:[TimerServiceBean.java]
 *@author: lhc
 *@time:2012-2-19 下午12:20:49 
 *@version: 1.0.0
 *测试EJB中构造函数和调用次数的关系
 */
@Stateless  
@Remote ({TimerService.class}) 
public class TimerServiceBean  implements TimerService
{
     private @Resource SessionContext ctx;  
     protected EntityManager em;   //实体管理实例
     protected Timer timer = null;
     public TimerServiceBean()
     {
     }
     
     public void scheduleTimer(long milliseconds)  
     {  
      //创建为间隔定时器
         ctx.getTimerService().createTimer(new Date(new Date().getTime()),milliseconds, "Hello world... ...");
         
     }
     
     /**
      * @param timer
      * 定期处理离线设备
      */
     @Timeout  
     public void timeoutHandler(Timer timer)  
     {  
      
     System.out.println("Hello world from Timer!");
     }

  @Override
  public boolean cancelTimer() 
  {
   int iterTimersSize = ctx.getTimerService().getTimers().size();
   if (iterTimersSize > 0)
   {
     Iterator iterTimers = ctx.getTimerService().getTimers().iterator();
     System.out.println("Timer number -> "+ iterTimersSize);
     while(iterTimers.hasNext())
     {
      this.timer = (Timer) iterTimers.next();
      this.timer.cancel();
     }
     return true;
      
   }
   else
   {
    return false;
   }
  }

 
}

测试程序

package examples.timer.Inface;

import java.util.Date;  
import java.util.Hashtable;  
import javax.naming.Context;  
import javax.naming.InitialContext;   

import examples.timer.remote.TimerService;
public class TaskClient  
{  
    public static void main(String[] args)  
    {  
        Hashtable evn = new Hashtable();  
        evn.put(Context.PROVIDER_URL, "127.0.0.1:1099");  
        evn.put(Context.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");   
        try  
        {  
            System.out.println(new Date().getTime());  
            InitialContext ctx=new InitialContext(evn);  
            TimerService timer = (TimerService) ctx.lookup("TimerServiceBean/remote");  
           // timer.scheduleTimer((long)1000*2);
           System.out.println(timer.cancelTimer());
            System.out.println("定时器已经启动");  
        }   
        catch (Exception e)  
        {    
            e.printStackTrace();  
        }  
          
    }  
}

希望对大家有一点帮助，哈哈。