Spring Task Execution and Scheduling Simple Example 工作排程器 @ MISTECH 技術手抄本

上次介紹 Spring Quartz Job Schedule Simple Example 工作排程器，現在再來使用 Spring 原生的 Task Execution and Scheduling，首先來瞭解一下 @Scheduled annotation 的意思

This annotation is used for task scheduling. The trigger information needs to be provided along with this annotation. You can use the properties fixedDelay/fixedRate/cron to provide the triggering information.

1. fixedRate: makes Spring run the task on periodic intervals even if the last invocation may be still running. 固定時間執行，不管上一次是否結束
2. fixedDelay: specifically controls the next execution time when the last execution finishes. 上一次執行結束後，再依設定的固定時間執行
3. cron: is a feature originating from Unix cron utility and has various options based on your requirements. BJ4(就不解釋了)

方法 1) Task scheduling using fixed delay attribute in @Scheduled annotation

Step 01: 設定 applicationContext.xml，將 task 選取

applicationContext

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xmlns:aop="http://www.springframework.org/schema/aop"
   xmlns:cache="http://www.springframework.org/schema/cache"
   xmlns:context="http://www.springframework.org/schema/context"
   xmlns:tx="http://www.springframework.org/schema/tx"
   xmlns:jpa="http://www.springframework.org/schema/data/jpa"
   xmlns:jee="http://www.springframework.org/schema/jee"
   xmlns:task="http://www.springframework.org/schema/task"
   xsi:schemaLocation="http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache.xsd
       http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-4.2.xsd
       http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-4.2.xsd
       http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
       http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.8.xsd
       http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">

   
   <task:annotation-driven/>
   <bean id="SpringTask-Annotation" class="com.mis.demo.SpringTaskAnnotationDemo"/>


</beans>

Step 02: 建立 SpringTaskAnnotationDemo.java

package com.mis.demo;

import java.util.Date;
import org.springframework.scheduling.annotation.Scheduled;
public class SpringTaskAnnotationDemo {
   @Scheduled(fixedDelay = 5000)
   //@Scheduled(fixedRate = 5000)
   public void demoServiceMethod()
   {
       System.out.println("Method executed at every 5 seconds. Current time is :: "+ new Date());
   }
}

這樣就可以運作了，簡單吧 !!

方法 2) Task scheduling using cron expression in @Scheduled annotation

Step 01: 在 applicationContext.xml 設定 class 的 task:scheduled 執行方法，所以在 SpringTaskExecutorDemo.java 的執行 method 為 execute。

<bean id="SpringTask-Cron" class="com.mis.demo.SpringTaskExecutorDemo"/>
   <task:scheduled-tasks>
       <task:scheduled ref="SpringTask-Cron" method="execute" cron="*/5 * * * * ?"/>
   </task:scheduled-tasks>

Step 02: 建立 SpringTaskExecutorDemo.java

package com.mis.demo;

import java.util.Calendar;

public class SpringTaskExecutorDemo {
   public void execute () {
       System.out.println("SpringTaskExecutorDemo: Run at " + Calendar.getInstance().getTimeInMillis() );
   }
}

這樣就可以運作了，也很簡單吧 !!

參考:

http://howtodoinjava.com/spring/spring-core/4-ways-to-schedule-tasks-in-spring-3-scheduled-example/

http://jimwayne.blogspot.tw/2014/04/spring-framework.html

http://docs.spring.io/spring/docs/current/spring-framework-reference/html/scheduling.html