spring進階教程(三)：定時任務

前言

前幾節咱們用第三方框架quarz實現了定時任務，實際上spring3.1開始，spring已經內置了定時任務的支持，實現很是簡單，下面咱們一塊兒看看怎麼實現

ScheduleApplication.java

其中重點是@EnableScheduling註解，表示啓動定時任務支持

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()));
    }
}

核心重點是@Scheduled註解，@Scheduled支持多種類型的計劃任務：cron、fixDelay、fixRate,最流行的仍是cron表達式，
在這裏推薦一個cron表達式在線生成器:http://cron.qqe2.com/

功能很強大，能夠圖形化配置cron表達式，也能夠泛解析cron表達式的執行時間，特別方便

 

運行項目

控制檯打印以下：

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交替執行，由於咱們配置的cron表達式是：sayHi方法從0秒開始，每兩秒執行一次；sayHello方法從1秒開始，每兩秒執行一次。

到此，咱們的定時任務運行成功！