定時(shí)任務(wù)DemoSchedule

public class DemoSchedule implements SchedulingConfigurer{
    private final Logger logger = LoggerFactory.getLogger(DemoSchedule.class);
    private static final String cron= "0 0 02 * * ?";
    @Autowired
    private DistributedLock redisLock;

    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
        taskRegistrar.addTriggerTask(new Task(redisLock),new DemoTrigger());
    }

    private static class Task implements Runnable{
        
        private DistributedLock redisLock;
        
        public Task(DistributedLock redisLock;){
            this.redisLock= redisLock;
        }
       
        @Override
        public void run() {
            boolean lockSuccess = redisLock.tryGetLock("demoId", 5000L * 60);
            if(! lockSuccess) {
                logger.info("demoId has started at other point...");
                return;
            }
            delayHandler();
        }

        private void delayHandler(){
           //do something
        }
    }

    private class DemoTrigger implements Trigger{
        @Override
        public Date nextExecutionTime(TriggerContext triggerContext) {
            CronTrigger trigger = new CronTrigger(cron);
            Date nextExec = trigger.nextExecutionTime(triggerContext);
            logger.debug("cron now:[{}]", cron);
            return nextExec;
        }
    }
}

redis分布式鎖

public class DistributedLock {

    public static final Logger logger = LoggerFactory.getLogger(DistributedLock.class);

    public static final String BILL_PREFIX = "locked_bill_";

    private final String LOCK_VALUE = "lock_value";

    @Autowired
    private RedisTemplate redisTemplate;

    private DistributedLock() {}

    /**
     * 嘗試獲取分布式鎖
     * @param lockKey 鎖
     * @param expireTime 超期時(shí)間
     * @return 是否獲取成功
     */
    public synchronized boolean tryGetLock(String lockKey, Long expireTime) {
        try {
            /*該方法會(huì)在沒有key時(shí)鲸匿，設(shè)置key;存在key時(shí)返回false；因此可以通過該方法及設(shè)置key的有效期，判斷是否有其它線程持有鎖*/
            Boolean success = redisTemplate.opsForValue().setIfAbsent(lockKey, LOCK_VALUE);
            if(success != null && success) {
                redisTemplate.expire(lockKey, expireTime, TimeUnit.MILLISECONDS);
                return true;
            }
            return false;
        } catch (Exception e) {
            logger.error("[tryGetDistributedLock] error", e);
            return false;
        }
    }

    /**
     * 釋放分布式鎖
     * @param lockKey 鎖
     * @return 是否釋放成功
     */
    public boolean releaseLock(String lockKey) {
        try {
            redisTemplate.delete(lockKey);
        } catch (Exception e) {
            logger.error("[releaseDistributedLock] error", e);
            return false;
        }
        return true;
    }
}