Java EE中的@Schedule无法启动 [英] @Schedule in Java EE doesn't start

问题描述

我正在开发一个java ee的web应用程序，我想每x次更新天气。这是我想要每20秒执行一次的代码，但它没有启动，有人能解释一下为什么吗？我必须在某个地方调用它？

I'm developing a web app in java ee and i want to update the weather every x amount of time. This is the code that i want to execute every 20 seconds but it does not start, can someone explain me why? I have to call it somewhere?

@Startup
@Singleton
public class ManageForecast implements Serializable{

private String urlQuery;
private String woeid;
private String cityHome;
private String tempHome;
private List<Location> place;
private Forecast forecast;

@PersistenceContext
EntityManager em;

@Schedule(second = "*/20", minute = "*", hour = "*")
public void updateForecast(){
    try {
        System.out.println("PARTITO!!!");
        place = em.createQuery("select l from Location l").getResultList();
        for (Location location : place) {
            forecast(location);
        }

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

}

推荐答案

它对我有用。我将GF3与Eclipse EJB-Project和以下代码一起使用：

It worked for me. I used GF3 with an Eclipse EJB-Project and the following code:

@Startup

@Singleton
public class ManageForecast implements Serializable{

//  private String urlQuery;
//  private String woeid;
//  private String cityHome;
//  private String tempHome;

@Schedule(second = "*/20", minute = "*", hour = "*")
public void updateForecast(){
    try {
        System.out.println("PARTITO!!!");
        //        place = em.createQuery("select l from Location l").getResultList();
        //        for (Location location : place) {
        //            forecast(location);
        //        }

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

    }
}

输出：

2015-01-22T16：28：40.015 + 0100 |信息：PARTITO !!!
2015-01-22T16：29：00.005 + 0100 |信息：PARTITO !!!

2015-01-22T16:28:40.015+0100|Information: PARTITO!!! 2015-01-22T16:29:00.005+0100|Information: PARTITO!!!

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