-- lua加锁脚本
-- KEYS[1],ARGV[1],ARGV[2]分别对应了orderId，uuid，3
-- 如果setnx成功，则继续expire命令逻辑
if redis.call('setnx',KEYS[1],ARGV[1]) == 1 
    then 
      -- 则给同一个key设置过期时间
       redis.call('expire',KEYS[1],ARGV[2]) 
       return 1 
    else 
      -- 如果setnx失败，则返回0
       return 0 
end

-- lua解锁脚本
-- KEYS[1],ARGV[1]分别对应了orderId，uuid
-- 若无法获取orderId缓存，则认为已经解锁
if redis.call('get',KEYS[1]) == false 
    then 
        return 1 
    -- 若获取到orderId，并value值对应了uuid，则执行删除命令
    elseif redis.call('get',KEYS[1]) == ARGV[1] 
    then 
        -- 删除缓存中的key
    	return redis.call('del',KEYS[1]) 
    else 
        -- 若获取到orderId，且value值与存入时不一致，则返回特殊值，方便进行后续逻辑
        return 2 
end

SoRedisLock soJimLock = null;
try{
    soJimLock = new SoRedisLock("orderId", jimClient);
    if (!soJimLock.lock(3)) {
        log.error("订单创建加锁失败");
        throw new BPLException("订单创建加锁失败");
    }
} catch(Exception e) {
    throw e;
} finally {
    if (null != soJimLock) {
        soJimLock.unlock();
    }
}

public class SoRedisLock{

    /** 加锁标志 */
    public static final String LOCKED = "TRUE";
    /** 锁的关键词 */
    private String key;
    private Cluster jimClient;
    
    /**
     * lock的构造函数
     * 
     * @param key
     *            key+"_lock" (key使用唯一的业务单号)
     * @param
     *
     */
    public SoRedisLock(String key, Cluster jimClient)
    {
        this.key = key + "_LOCK";
        this.jimClient = jimClient;
    }
    
    /**
     * 加锁
     *
     * @param expire
     *            锁的持续时间（秒），过期删除
     * @return 成功或失败标志
     */
    public boolean lock(int expire)
    {
        try
        {
            log.info("分布式事务加锁，key：{}", this.key);   
            String lua_scripts = "if redis.call('setnx',KEYS[1],ARGV[1]) == 1 then " +
            		"redis.call('expire',KEYS[1],ARGV[2]) return 1 else return 0 end";
            String sha = jimClient.scriptLoad(lua_scripts);
            List<String> keys = new ArrayList<>();
            List<String> values = new ArrayList<>();
            keys.add(this.key);
            values.add(LOCKED);
            values.add(String.valueOf(expire));
            this.locked = jimClient.evalsha(sha, keys, values, false).equals(1L);
            return this.locked;
        } catch (Exception e){
        	throw new RuntimeException("Locking error", e);
        }
    }

    /**
     * 解锁 无论是否加锁成功，都需要调用unlock 建议放在finally 方法块中
     */
    public void unlock()
    {
        if (this.jimClient == null || !this.locked) {
            return ;
        }
        try {
        String luaScript = "if redis.call('get',KEYS[1]) == false then return 1 " +
        		"elseif redis.call('get',KEYS[1]) == ARGV[1] then " +
        		"return redis.call('del',KEYS[1]) else return 2 end";
        String sha = jimClient.scriptLoad(luaScript);
        if(!jimClient.evalsha(sha, Collections.singletonList(this.key), Collections.singletonList(LOCKED), false).equals(1L)){
        	throw new RuntimeException("解锁失败,key:"+this.key);
        }
        } catch (Exception e) {
                log.error("unLocking error, key:{}", this.key, e);
        	throw new RuntimeException("unLocking error, key:"+this.key);
        }
    }
}