mysql+springboot+mybatis+Lambda 表达式实现定时任务

数据库

DROP DATABASE IF EXISTS `socks`;
CREATE DATABASE `socks`;
USE `SOCKS`;
DROP TABLE IF EXISTS `cron`;
CREATE TABLE `cron`  (
  `cron_id` varchar(30) NOT NULL PRIMARY KEY,
  `cron` varchar(30) NOT NULL  
);
INSERT INTO `cron` VALUES ('1', '0/8 * * * * ?');

pom.xml

<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter</artifactId>
		<version>2.0.4.RELEASE</version>
	</parent>

	<dependencies>
		<dependency><!--添加Web依赖 -->
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<dependency><!--添加MySql依赖 -->
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
		</dependency>
		<dependency><!--添加Mybatis依赖 配置mybatis的一些初始化的东西 -->
			<groupId>org.mybatis.spring.boot</groupId>
			<artifactId>mybatis-spring-boot-starter</artifactId>
			<version>1.3.1</version>
		</dependency>
		<dependency><!-- 添加mybatis依赖 -->
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis</artifactId>
			<version>3.4.5</version>
			<scope>compile</scope>
		</dependency>
		<dependency>
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis-spring</artifactId>
			<version>1.3.1</version>
			<scope>compile</scope>
		</dependency>
	</dependencies>

application.yml

#application.yml 配置如下：
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/socks
    username: root
    password: root

StaticScheduleTaskApplication

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

/**
 * Hello world!
 *
 */
@SpringBootApplication
public class StaticScheduleTaskApplication {
    public static void main(String[] args) {
        SpringApplication.run(StaticScheduleTaskApplication.class, args);
    }
}

DynamicScheduleTask

import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.SchedulingConfigurer;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;
import org.springframework.scheduling.support.CronTrigger;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;

import java.time.LocalDateTime;

/**
* @Description:    
* @Author:         宫崎不骏
* @CreateDate:     2020年1月7日 下午6:15:18
* @UpdateUser:
* @UpdateDate:     2020年1月7日 下午6:15:18
* @UpdateRemark:   修改内容
* @Version:        1.0
*/
@Component
@Configuration      //1.主要用于标记配置类，兼备Component的效果。
@EnableScheduling   // 2.开启定时任务
public class DynamicScheduleTask implements SchedulingConfigurer {

	@Mapper
	public interface CronMapper {
		@Select("select cron from cron limit 1")
		String getCron();
	}

	@Autowired      //注入mapper
	@SuppressWarnings("all")
	CronMapper cronMapper;

	/**
	 * 执行定时任务.
	 */
	@Override
	public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {

		taskRegistrar.addTriggerTask(
				//1.添加任务内容(Runnable)
				() -> System.out.println("执行动态定时任务: " + LocalDateTime.now().toLocalTime()),
				//2.设置执行周期(Trigger)
				triggerContext -> {
					//2.1 从数据库获取执行周期
					String cron = cronMapper.getCron();
					//2.2 合法性校验.
					if (StringUtils.isEmpty(cron)) {
						// Omitted Code ..
					}
					//2.3 返回执行周期(Date)
					return new CronTrigger(cron).nextExecutionTime(triggerContext);
				}
		);
	}

}

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