修改定时任务不重启项目，SpringBoot如何实现？

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Java知音 2021-12-20 14:30:14

业务场景描述：定时任务的任务名称，cron（定时任务表达式），定时任务开关，存储在数据库表中。在不重启项目的情况下，修改定时任务表达式，可以实时获取新的定时任务执行时间规则；修改定时任务执行状态，可以随时开关定时任务。

使用技术：基于接口 SchedulingConfigurer

1、建表管理定时任务

DROP TABLE IF EXISTS `scheduled`;
CREATE TABLE `scheduled` (
  `name` varchar(20) DEFAULT NULL,
  `cron` varchar(30) DEFAULT NULL,
  `open` tinyint(1) DEFAULT NULL COMMENT '1开启， 其他为关闭'
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of scheduled
-- ----------------------------
INSERT INTO `scheduled` VALUES ('demo1', '0/5 * * * * ?', '1');
INSERT INTO `scheduled` VALUES ('demo2', '0/6 * * * * ?', '1');

2、代码实现

定时任务配置类：

package com.example.demo.scheduled;

import com.google.common.util.concurrent.ThreadFactoryBuilder;
import org.springframework.context.annotation.Bean;
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 java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;

/**
 * @Description: 基于接口SchedulingConfigurer的动态定时任务
 * @Author: 
 */
@Configuration
@EnableScheduling
public abstract class ConfigurerSchedulingDemo implements SchedulingConfigurer {

    //定时任务周期表达式
    private String cron;
    /** 
     * @Description:  重写配置定时任务的方法
     * @param: scheduledTaskRegistrar 
     * @return: void 
     * @Author: 
     */
    @Override
    public void configureTasks(ScheduledTaskRegistrar scheduledTaskRegistrar) {
        scheduledTaskRegistrar.setScheduler(taskScheduler());
        scheduledTaskRegistrar.addTriggerTask(
                //执行定时任务
                () ->
                {
                    taskService();
                },
                //设置触发器
                triggerContext -> {

                   cron = getCron();//获取定时任务周期表达式

                    CronTrigger trigger = new CronTrigger(cron);

                    return trigger.nextExecutionTime(triggerContext);
                }
        );

    }

    @Bean
    public Executor taskScheduler() {
        //设置线程名称
        ThreadFactory namedThreadFactory = new ThreadFactoryBuilder().setNameFormat("demo-pool-%d").build();
        //创建线程池
        return Executors.newScheduledThreadPool(5, namedThreadFactory);
    }

    /**
     * @Description: 执行定时任务
     * @param:
     * @return: void
     * @Author: 
     */
    public abstract void taskService();

    /**
     * @Description: 获取定时任务周期表达式
     * @param:
     * @return: java.lang.String
     * @Author: 
     * @Date: 2020/8/28
     */
    public abstract String getCron();

}

定时任务1

package com.example.demo.scheduled;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.example.demo.dao.CronMapper;
import com.example.demo.entity.Scheduled;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;

import java.time.LocalDateTime;

/**
 * @Description:
 * @Author: 
 */
@Configuration
public class TaskDemo extends ConfigurerSchedulingDemo {

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

    @Override
    public void taskService() {
        Integer open = getOpen();
        if (1== open){
            System.out.println("定时任务demo1:"
                    + LocalDateTime.now()+"，线程名称："+Thread.currentThread().getName()
                    + " 线程id："+Thread.currentThread().getId());
        }
    }

    @Override
    public String getCron() {
        QueryWrapper<Scheduled> queryWrapper = new QueryWrapper<>();
        queryWrapper.eq("name","demo1");
        String cron = cronMapper.selectOne(queryWrapper).getCron();
        return cron;
    }

    public Integer getOpen() {
        QueryWrapper<Scheduled> queryWrapper = new QueryWrapper<>();
        queryWrapper.eq("name", "demo1");
        Integer open = cronMapper.selectOne(queryWrapper).getOpen();
        return open;
    }

}

定时任务2

package com.example.demo.scheduled;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.example.demo.dao.CronMapper;
import com.example.demo.entity.Scheduled;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;

import java.time.LocalDateTime;

/**
 * @Description:
 * @Author: 
 */
@Configuration
public class TaskDemo1 extends ConfigurerSchedulingDemo {

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

    @Override
    public void taskService() {
        Integer open = getOpen();
        if (1== open){
            System.out.println("定时任务demo2:"
                    + LocalDateTime.now()+"，线程名称："+Thread.currentThread().getName()
                    + " 线程id："+Thread.currentThread().getId());
        }
    }

    @Override
    public String getCron() {
        QueryWrapper<Scheduled> queryWrapper = new QueryWrapper<>();
        queryWrapper.eq("name","demo2");
        String cron = cronMapper.selectOne(queryWrapper).getCron();
        return cron;
    }

    public Integer getOpen() {
        QueryWrapper<Scheduled> queryWrapper = new QueryWrapper<>();
        queryWrapper.eq("name", "demo2");
        Integer open = cronMapper.selectOne(queryWrapper).getOpen();
        return open;
    }
}