Timer类

public static void main(String[] args){
		TimerTask timerTask = new TimerTask() {
			@Override
			public void run() {
				System.out.println("Timer方式执行一次定时任务");
			}
		};
		new Timer().schedule(timerTask,1,2*1000);
	}

ScheduledExecutorService类

ScheduledExecutorService,是基于线程设计的定时任务类，每个调度任务都会分配到线程池中的一个线程去并行执行

public static void main(String[] args){
		ScheduledExecutorService scheduledExecutor = Executors.newSingleThreadScheduledExecutor();
		scheduledExecutor.scheduleAtFixedRate(
				new Runnable() {
					@Override
					public void run() {
						System.out.println("ScheduledExecutorService方式执行一次定时任务");
					}
				}
		,0,5, TimeUnit.SECONDS);
	}

Quartz

1. 引入quartz依赖

   <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-quartz</artifactId>
   </dependency>
   

2. 配置JobDetail和Trigger

   @Configuration
   public class QuartzConfig {
       @Bean
       public JobDetail quartzDetail(){
           return JobBuilder.newJob(QuartzTest.class).withIdentity("QuartzTest").storeDurably().build();
       }
       @Bean
       public SimpleTrigger quartzTrigger(){
           SimpleScheduleBuilder scheduleBuilder = SimpleScheduleBuilder.simpleSchedule()
                   .withIntervalInSeconds(10)
                   .repeatForever();
           //CronScheduleBuilder cron= CronScheduleBuilder.cronSchedule("0/10 * * * * ?");
           return TriggerBuilder.newTrigger().forJob(quartzDetail())
                   .withIdentity("QuartzTest")
                   .withSchedule(scheduleBuilder)
                   .build();
       }
   }
   
   

3. 测试

   public class QuartzTest extends QuartzJobBean {
       @Override
       protected void executeInternal(JobExecutionContext jobExecutionContext){
           System.out.println("quartz执行一次定时任务 ");
       }
   }
   

Scheduled注解

1. Spring3.0以后自带的task，在启动类上使用@EnableScheduling开启定时任务支持

2. 使用

   @Component
   public class ScheduledTest {
       private Logger logger = LoggerFactory.getLogger(ScheduledTest.class);
       /**
        * 每3秒执行一次定时任务
        */
      @Scheduled(fixedRate = 3000) 
       public void testCron(){
           logger.info("Scheduled 执行一次定时任务");
       }
   }
   

3. @Scheduled(initialDelay = 1000, fixedRate = 3000) 第一次延迟1秒后执行，之后按 fixedRate 的规则每 3 秒执行一次

4. @Scheduled(cron = "0/10 * * * * ? ")通过 cron 表达式定义规则