Redis分布式事务锁之核心代码

 

分享一下最近学习Redis分布式事务锁的核心代码，主要解决高并发情况下分布式事务的同步问题。

@RestController
public class IndexController {

private static final Logger logger = LoggerFactory.getLogger(IndexController.class);

@Autowired
private Redisson redisson;
@Autowired
private StringRedisTemplate stringRedisTemplate;

@RequestMapping("/deduct_stock")
public String deductStock() throws InterruptedException {
String lockKey = "product_001";
//String clientId = UUID.randomUUID().toString();
RLock redissonLock = redisson.getLock(lockKey);
try {
//Boolean result = stringRedisTemplate.opsForValue().setIfAbsent(lockKey, "zhuge"); //jedis.setnx(key,value)
//stringRedisTemplate.expire(lockKey,30, TimeUnit.SECONDS);
/*Boolean result = stringRedisTemplate.opsForValue().setIfAbsent(lockKey, clientId, 30, TimeUnit.SECONDS);

if (!result) {
return "1001";
}*/

// 加锁，实现锁续命功能
redissonLock.lock();
int stock = Integer.parseInt(stringRedisTemplate.opsForValue().get("stock")); // jedis.get("stock")
if (stock > 0) {
int realStock = stock - 1;
stringRedisTemplate.opsForValue().set("stock", realStock + ""); // jedis.set(key,value)
System.out.println("扣减成功，剩余库存:" + realStock + "");
} else {
System.out.println("扣减失败，库存不足");
}
}finally {
redissonLock.unlock();
/*if (clientId.equals(stringRedisTemplate.opsForValue().get(lockKey))){
stringRedisTemplate.delete(lockKey);
}*/
}
return "end";
}

@RequestMapping("/redlock")
public String redlock() throws InterruptedException {
String lockKey = "product_001";
//这里需要自己实例化不同redis实例的redisson客户端连接，这里只是伪代码用一个redisson客户端简化了
RLock lock1 = redisson.getLock(lockKey);
RLock lock2 = redisson.getLock(lockKey);
RLock lock3 = redisson.getLock(lockKey);

/**
* 根据多个 RLock 对象构建 RedissonRedLock （最核心的差别就在这里）
*/
RedissonRedLock redLock = new RedissonRedLock(lock1, lock2, lock3);
try {
/**
* 4.尝试获取锁
* waitTimeout 尝试获取锁的最大等待时间，超过这个值，则认为获取锁失败
* leaseTime 锁的持有时间,超过这个时间锁会自动失效（值应设置为大于业务处理的时间，确保在锁有效期内业务能处理完）
*/
boolean res = redLock.tryLock(10, 30, TimeUnit.SECONDS);
if (res) {
//成功获得锁，在这里处理业务
}
} catch (Exception e) {
throw new RuntimeException("lock fail");
} finally {
//无论如何, 最后都要解锁
redLock.unlock();
}

return "end";
}

}