前言
前几节我们用第三方框架quarz实现了定时任务，实际上spring3.1开始，spring已经内置了定时任务的支持，实现非常简单，下面我们一起看看怎么实现
参考项目：https://github.com/bigbeef/cppba-sample
开源地址：https://github.com/bigbeef
个人博客：http://blog.cppba.com
ScheduleApplication.java
其中重点是@EnableScheduling注解，表示启动定时任务支持
package com.cppba;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableScheduling;
@SpringBootApplication
@EnableScheduling
public class ScheduleApplication {
public static void main(String[] args) {
SpringApplication.run(ScheduleApplication.class, args);
}
}
SaySchedule.java
package com.cppba.schedule;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
@Component
public class SaySchedule {
private DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
@Scheduled(cron = "0/2 * * * * ?")
public void sayHi() {
System.out.println("hi! time is :" + df.format(new Date()));
}
@Scheduled(cron = "1/2 * * * * ?")
public void sayHello() {
System.out.println("hello! time is :" + df.format(new Date()));
}
}
核心重点是@Scheduled注解，@Scheduled支持多种类型的计划任务：cron、fixDelay、fixRate,最流行的还是cron表达式，
在这里推荐一个cron表达式在线生成器:http://cron.qqe2.com/
功能很强大，可以图形化配置cron表达式，也可以泛解析cron表达式的执行时间，特别方便
运行项目
控制台打印如下：
hi! time is :2017-08-22 22:40:08
hello! time is :2017-08-22 22:40:09
hi! time is :2017-08-22 22:40:10
hello! time is :2017-08-22 22:40:11
hi! time is :2017-08-22 22:40:12
hello! time is :2017-08-22 22:40:13
hi! time is :2017-08-22 22:40:14
hello! time is :2017-08-22 22:40:15
hi! time is :2017-08-22 22:40:16
hello! time is :2017-08-22 22:40:17
hi! time is :2017-08-22 22:40:18
hello! time is :2017-08-22 22:40:19
hi! time is :2017-08-22 22:40:20
hello! time is :2017-08-22 22:40:21
hi! time is :2017-08-22 22:40:22
hello! time is :2017-08-22 22:40:23
hi! time is :2017-08-22 22:40:24
hello和hi交替执行，因为我们配置的cron表达式是：sayHi方法从0秒开始，每两秒执行一次；sayHello方法从1秒开始，每两秒执行一次。
到此，我们的定时任务运行成功！
