Redis 分布式锁实现

redis 不可重入、非公平锁的实现

 

加锁使用 set 操作

解锁使用lua脚本

local key= KEYS[1]
local lockId=ARGV[1]

local result=0
local val= redis.call('get',key);

if(val==nil) then
    result=0
elseif (val==lockId) then
    redis.call('del',key)
    result=1
else
    result=2
end
return result

 

锁的实现:

package xxxxxxxxxxxxxxxxxxxxx.lock;

import com.google.common.base.Throwables;
import xxxxxxxxxx.R2mClusterClient;
import lombok.extern.slf4j.Slf4j;

import java.util.UUID;

/**
 * r2m 锁实现
 * Created by lxn on 2019/4/11.
 */
@Slf4j
public class R2mLock {

    /**
     * 释放锁的lua脚本
     */
    private static String relaseScript="local key= KEYS[1]\n" +
            "local lockId=ARGV[1]\n" +
            "\n" +
            "local result=0\n" +
            "local val= redis.call('get',key);\n" +
            "\n" +
            "if(val==nil) then\n" +
            "    result=0\n" +
            "elseif (val==lockId) then\n" +
            "    redis.call('del',key)\n" +
            "    result=1\n" +
            "else\n" +
            "    result=2\n" +
            "end\n" +
            "return result";


    /**
     * 最长锁时间
     */
    private long defaultLockTime =10000;

    /**
     * 锁的key
     */
    private String lockKey;

    /**
     * r2m客户端
     */
    private R2mClusterClient r2mClusterClient;

    private String lockId;


    public R2mLock(String lockKey, R2mClusterClient r2mClusterClient) {
        this.lockKey = lockKey;
        this.r2mClusterClient = r2mClusterClient;
    }

    /**
     * 获取锁
     * @param waitTime 毫秒
     * @throws LockTimeOutException
     */
    public void tryLock(long waitTime) throws LockTimeOutException {
        lockId= UUID.randomUUID().toString();
        long start=System.currentTimeMillis();

        while(System.currentTimeMillis()-start

锁的使用示例：

使用时记得要双重检查！

 

R2mLock lock=new R2mLock(key,r2mClusterClient);

try {
    lock.tryLock(3000);
    //业务代码

} catch (LockTimeOutException e) {
    throw new OrderTradeException(ErrorCodeEnum.GET_LOCK_ERROR);
}finally {
    lock.releaseLock();
}