java定时任务实现的4种方式

1. java自带的Timer

 Timer timer = new Timer();
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                System.out.println("Time's up!");

            }
        },3*1000,1000);

2.ScheduledThreadPool-线程池

  ScheduledExecutorService scheduledThreadPool = Executors.newScheduledThreadPool(2);
        scheduledThreadPool.scheduleAtFixedRate(new Runnable() {
            @Override
            public void run() {
                System.out.println("=========================");
            }
        }, 1000, 2000, TimeUnit.MILLISECONDS);

        scheduledThreadPool.scheduleAtFixedRate(new Runnable() {
            @Override
            public void run() {
                System.out.println(System.currentTimeMillis()+"<><>"+System.nanoTime());
            }
        }, 1000, 2000, TimeUnit.MILLISECONDS);

3.使用注解的形式：@Scheduled

@Component
public class SpringScheduled {

    @Scheduled(initialDelay = 2000,fixedDelay = 5000)
    public void doSomething() {
        System.out.println("Spring自带的Scheduled执行了=======================");
    }
}

//下面是开启
@SpringBootApplication
@EnableScheduling
public class DemoApplication {

    public static void main(String[] args) throws InterruptedException {
        SpringApplication application = new SpringApplication(DemoApplication.class);
        application.addListeners(new ContextRefreshedEventListener());
        application.run(args);
    }
}

4.使用Quartz定时任务调度器

配置

@Configuration
public class QuartzConfig {


    @Resource
    private ScheduleTask scheduleTask;

    /**
     * 配置定时任务1
     * @return
     */
    @Bean(name="firstJobDetail")
    public MethodInvokingJobDetailFactoryBean firstJobDetail(){
        MethodInvokingJobDetailFactoryBean method = new MethodInvokingJobDetailFactoryBean();
        // 为需要执行的实体类对应的对象
        method.setTargetObject(scheduleTask);
        // 需要执行的方法
        method.setTargetMethod("test");
        // 是否并发执行
        method.setConcurrent(false);
        return method;
    }


    /**
     *   配置触发器1
     *   @param firstJobDetail
     *   @return
     */
    @Bean(name="firstTrigger")
    public SimpleTriggerFactoryBean firstTrigger(JobDetail firstJobDetail){
        SimpleTriggerFactoryBean simpleBean = new SimpleTriggerFactoryBean();
        simpleBean.setJobDetail(firstJobDetail);
        // 设置任务启动延迟
        simpleBean.setStartDelay(1000);
        // 每1秒执行一次
        simpleBean.setRepeatInterval(1000);
        //设置重复计数
        //simpleBean.setRepeatCount(0);
        return simpleBean;
    }

    /**
     *  配置Scheduler
     */
    @Bean(name = "scheduler")
    public SchedulerFactoryBean schedulerFactoryBean(Trigger firstTrigger){
        SchedulerFactoryBean factoryBean = new SchedulerFactoryBean();
        //factoryBean.setTriggers(firstTrigger);
        return factoryBean;
    }



}

要执行的任务

@Component
public class ScheduleTask {

   public void test() {
       System.out.println("====================================");
   }

}

总结：

还有其他方式可以实现定时任务的方式，可以贴出来，讨论讨论