java定时任务

Spring Boot提供了@EnableScheduling和@Scheduled注解，用于支持定时任务的执行

方法一:利用scheduled注解

启动类加上@EnableScheduling, 这个注解内部@Import(SchedulingConfiguration.class) 引用了 SchedulingConfiguration类

@SpringBootApplication
@EnableScheduling  
@Configuration
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
        }
    }
//注意在类上加@Component注解,标注这个类为Spring容器的Bean

@Component
public class Task {
    @Scheduled(initialDelay = 1000, fixedRate = 10000)
    public void run() {
        System.out.println("Current time is :: " + Calendar.getInstance().getTime());
    }
}

方法二:重写configureTasks方法

类要继承SchedulingConfigurer

@Component
public class ConfigTask implements SchedulingConfigurer {
    //时间表达式  每2秒执行一次
    private String cron = "0/2 * * * * ?";
    private SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    @Override
    public void configureTasks(ScheduledTaskRegistrar scheduledTaskRegistrar) {
        scheduledTaskRegistrar.addTriggerTask(new Runnable() {
            @Override
            public void run() {
                System.out.println("当前时间为：" + sdf.format(new Date()));
            }
        }, new Trigger() {
            @Override
            public Date nextExecutionTime(TriggerContext triggerContext) {
                CronTrigger cronTrigger = new CronTrigger(cron);
                Date nextExecDate = cronTrigger.nextExecutionTime(triggerContext);
                return nextExecDate;
            }
        });
    }

    public void setCron(String cron) {
        this.cron = cron;
    }
}