Springboot自带定时任务实现动态配置Cron参数方式

目录

• Springboot自带定时任务实现动态配置Cron参数

• SpringBoot定时任务的四种实现方式(主要)

• SchedulingConfigurer接口实现动态加载cron表达式

public class TestTimer {
    public static void main(String[] args) {
        TimerTask timerTask = new TimerTask() {
            @Override
            public void run() {
                System.out.println("task  run:"+ new Date());
            }
        };
        Timer timer = new Timer();
        //安排指定的任务在指定的时间开始进行重复的固定延迟执行。这里是每3秒执行一次
        timer.schedule(timerTask,10,3000);
    }
}

public class TestScheduledExecutorService {
    public static void main(String[] args) {
        ScheduledExecutorService service = Executors.newSingleThreadScheduledExecutor();
        // 参数：1、任务体 2、首次执行的延时时间
        //      3、任务执行间隔 4、间隔时间单位
        service.scheduleAtFixedRate(()->System.out.println("task ScheduledExecutorService "+new Date()), 0, 3, TimeUnit.SECONDS);
    }
}

import java.util.Date;
import org.springframework.scheduling.Trigger;
import org.springframework.scheduling.TriggerContext;
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 java.time.LocalDateTime;
@Component 
@EnableScheduling
public class TaskCronChange implements  SchedulingConfigurer{
    public static String cron; 
    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
        //项目部署时，会在这里执行一次，从数据库拿到cron表达式
        cron = timerQueryMapper.getCronTime();
       Runnable task = new Runnable() {
           @Override
           public void run() {
              //任务逻辑代码部分.
              System.out.println("I am going:" + LocalDateTime.now());
           }
       };
       Trigger trigger = new Trigger() {
           @Override
           public Date nextExecutionTime(TriggerContext triggerContext) {
              //任务触发，可修改任务的执行周期.
              //每一次任务触发，都会执行这里的方法一次，重新获取下一次的执行时间        
              cron = timerQueryMapper.getCronTime();
              CronTrigger trigger = new CronTrigger(cron);
              Date nextExec = trigger.nextExecutionTime(triggerContext);
              return nextExec;
           }
       };
       taskRegistrar.addTriggerTask(task, trigger);
    }
}

@Component
@EnableScheduling
public class Test implements SchedulingConfigurer {
    @Override
    public void configureTasks(ScheduledTaskRegistrar scheduledTaskRegistrar) {
        //创建一个线程池调度器，默认是单线程执行
        ScheduledExecutorService executorService = Executors.newScheduledThreadPool(100);
        scheduledTaskRegistrar.setScheduler(executorService);
        //增加任务
        scheduledTaskRegistrar.addTriggerTask(new Task("test1"),new Trig("cronExpess1"));
        scheduledTaskRegistrar.addTriggerTask(new Task("test2"),new Trig("cronExpess2"));
        scheduledTaskRegistrar.addTriggerTask(new Task("test3"),new Trig("cronExpess2"));
    }
}
/**
 * 业务类
 */
class Task implements Runnable{
    String task;
    public Task(String task){
        this.task = task;
    }
    //具体业务
    @Override
    public void run() {
        System.out.println(task+":"+LocalDateTime.now()+","+Thread.currentThread().getName());
    }
}
/**
 * 调度类
 */
class Trig implements Trigger{ 
    private String cronExpress;
    public Trig(String cronExpress){
        this.cronExpress = cronExpress;
    }
    @Override
    public Date nextExecutionTime(TriggerContext triggerContext) {
        String cron = null;
        try {
            //每次调度时加载cron表达式
            cron = new Config().getCrons().get(cronExpress);
        } catch (IOException e) {
            e.printStackTrace();
        }
        CronTrigger cronTrigger = new CronTrigger(cron);
        return cronTrigger.nextExecutionTime(triggerContext);
    }
}
/**
 * 加载cron表达式
 */
class Config{
    private static Map<String,String> cronMap;
    private static long preModifyTime;
    private String cronFile = "config/application.properties";
    public Map<String,String> getCrons() throws IOException {
        File file = new File(cronFile);
        long nowModifyTime = file.lastModified();
        if (cronMap != null && nowModifyTime == preModifyTime){
            return cronMap;
        }else {
            cronMap = new HashMap<>();
            BufferedReader br = new BufferedReader(new FileReader(file));
            String line = null;
            while ((line = br.readLine()) != null){
                String[] s = line.split("=");
                cronMap.put(s[0].trim(),s[1].trim());
            }
            preModifyTime = nowModifyTime;
            return cronMap;
        }
    }
}

cronExpess1 = 0/5 * * * * *
cronExpess2 = 0/10 * * * * *