redis锁 Redlock

ゝ一纸荒年。 2022-05-24 09:48 162阅读 0赞

参考文章：[https://blog.csdn.net/pfnie/article/details/52234735\#commentBox][https_blog.csdn.net_pfnie_article_details_52234735_commentBox]

public class RedisUtil {
    
        //失效时间
        public static int ONE_DAY = 60 * 60 * 24;
    
    
        //锁的过期时间,秒
        private static long LOCK_EXPIRE = 60L;
    
        //锁的请求超时时间
        private static long LOCK_TIME_OUT = 10L * 1000000000L;
    
        //锁名称
        private static String LOCK_KEY = "lock";
    
        //锁的值
        private static String LOCK_VALUE = "1";
    
        public void lock(StringRedisTemplate template) {
            // 上锁时的时间
            long nowTime = System.nanoTime();
            //等待时间是否超时
            Random r = new Random();
            RedisConnection connection = template.getConnectionFactory().getConnection();
            try {
                long l = System.nanoTime() - nowTime;
                while (l < LOCK_TIME_OUT) {
                    // 锁是否存在
                    if (connection.setNX(LOCK_KEY.getBytes(), LOCK_VALUE.getBytes())) {
                        //锁不存在，设置锁的有效期，然后跳出循环，上锁方法结束
                        template.expire(LOCK_KEY, LOCK_EXPIRE, TimeUnit.SECONDS);
                        break;
                    } else {
                        //锁存在，则重试。设置随机的延迟时间，避免不同客户端同时重试导致谁都无法拿到锁
                        Thread.sleep(5, r.nextInt(100));
                        l = System.nanoTime() - nowTime;
                    }
                }
                if (l > LOCK_TIME_OUT) {
                    System.out.println("超时");
                    System.out.println("执行时间:" + l);
                }
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                connection.close();
            }
        }
    
        public void unLock(StringRedisTemplate template) {
            template.delete(LOCK_KEY);
        }
    }

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