SpringBoot基于Redis的分布式锁_springboot+redis+thredlocal-优快云博客

本文链接：https://blog.youkuaiyun.com/weixin_44420955/article/details/103628963

本文详细介绍了一种基于SpringBoot和Redis实现的分布式锁机制，包括接口定义、具体实现及测试方法。通过Lua脚本确保锁的安全释放，适用于高并发场景。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

SpringBoot基于Redis的分布式锁

前置条件：

配置maven依赖、redis连接参数和redisTemplate

Redis锁：

接口

package com.xpf.config.redis.lock;

/**
 * @Title:RedisLock
 * @Package:com.xpf.config.redis
 * @Author: xiapf
 * @Date:2019/12/13
 * @Descrption:
 */
public interface RedisLock {

    long TIMEOUT_MILLIS = 30000;
    int RETRY_TIMES = Integer.MAX_VALUE;
    long SLEEP_MILLIS = 500;

    boolean lock(String key, long expire, int retryTimes, long sleepMillis);

    boolean releaseLock(String key);

}

实现类

package com.xpf.config.redis.lock;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.dao.DataAccessException;
import org.springframework.data.redis.connection.RedisConnection;
import org.springframework.data.redis.core.RedisCallback;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisCluster;
import redis.clients.jedis.JedisCommands;

import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

/**
 * @Title:RedisLockImpl
 * @Package:com.xpf.config.redis.lock
 * @Author: xiapf
 * @Date:2019/12/13
 * @Descrption:
 */
@Component
public class RedisLockImpl implements RedisLock {
    private final Logger logger = LoggerFactory.getLogger(RedisLockImpl.class);

    private RedisTemplate<Object, Object> redisTemplate;

    private ThreadLocal<String> lockFlag = new ThreadLocal<String>();

    public static final String UNLOCK_LUA;

    static {
        StringBuilder sb = new StringBuilder();
        sb.append("if redis.call(\"get\",KEYS[1]) == ARGV[1] ");
        sb.append("then ");
        sb.append("    return redis.call(\"del\",KEYS[1]) ");
        sb.append("else ");
        sb.append("    return 0 ");
        sb.append("end ");
        UNLOCK_LUA = sb.toString();
    }

    public RedisLockImpl(RedisTemplate<Object, Object> redisTemplate) {
        super();
        this.redisTemplate = redisTemplate;
    }

    @Override
    public boolean lock(String key, long expire, int retryTimes, long sleepMillis) {
        boolean result = setRedis(key, expire);
        // 如果获取锁失败，按照传入的重试次数进行重试
        while((!result) && retryTimes-- > 0){
            try {
                logger.debug("lock failed, retrying..." + retryTimes);
                Thread.sleep(sleepMillis);
            } catch (InterruptedException e) {
                return false;
            }
            result = setRedis(key, expire);
        }
        return result;
    }

    private boolean setRedis(String key, long expire) {
        try {
            String result = redisTemplate.execute(new RedisCallback<String>() {
                @Override
                public String doInRedis(RedisConnection connection) throws DataAccessException {
                    JedisCommands commands = (JedisCommands) connection.getNativeConnection();
                    String uuid = UUID.randomUUID().toString();
                    lockFlag.set(uuid);
                    return commands.set(key, uuid, "NX", "PX", expire);
                }
            });
            return !StringUtils.isEmpty(result);
        } catch (Exception e) {
            logger.error("set redis occured an exception", e);
        }
        return false;
    }

    @Override
    public boolean releaseLock(String key) {
        // 释放锁的时候，有可能因为持锁之后方法执行时间大于锁的有效期，此时有可能已经被另外一个线程持有锁，所以不能直接删除
        try {
            List<String> keys = new ArrayList<String>();
            keys.add(key);
            List<String> args = new ArrayList<String>();
            args.add(lockFlag.get());

            // 使用lua脚本删除redis中匹配value的key，可以避免由于方法执行时间过长而redis锁自动过期失效的时候误删其他线程的锁
            // spring自带的执行脚本方法中，集群模式直接抛出不支持执行脚本的异常，所以只能拿到原redis的connection来执行脚本

            Long result = redisTemplate.execute(new RedisCallback<Long>() {
                @Override
                public Long doInRedis(RedisConnection connection) throws DataAccessException {
                    Object nativeConnection = connection.getNativeConnection();
                    // 集群模式和单机模式虽然执行脚本的方法一样，但是没有共同的接口，所以只能分开执行
                    // 集群模式
                    if (nativeConnection instanceof JedisCluster) {
                        return (Long) ((JedisCluster) nativeConnection).eval(UNLOCK_LUA, keys, args);
                    }

                    // 单机模式
                    else if (nativeConnection instanceof Jedis) {
                        return (Long) ((Jedis) nativeConnection).eval(UNLOCK_LUA, keys, args);
                    }
                    return 0L;
                }
            });

            return result != null && result > 0;
        } catch (Exception e) {
            logger.error("release lock occured an exception", e);
        }
        return false;
    }

}

测试：

    @Autowired
    RedisLock redisLock;
    @Test
    public void test1() {
        String key = UUID.randomUUID().toString();
        System.out.println(key);
        IntStream.range(1, 1000).parallel().forEach(i -> {
            try {
                boolean lock = redisLock.lock(key, RedisLock.TIMEOUT_MILLIS, RedisLock.RETRY_TIMES, RedisLock.SLEEP_MILLIS);
                if (lock) {
                    Thread.sleep(100);
                    if (count > 0) {
                        int count = getCount();
                        System.out.println("第" + i + "个人的count:" + count);
                    }
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            } finally {
                redisLock.releaseLock(key);
            }
        });
    }