java定时任务实现的4种方式

布满荆棘的人生 2022-04-05 11:41 232阅读 0赞

# 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