redis分布式锁的使用
一 本身自带的方法进行使用:
<dependency> <groupId>redis.clients</groupId> <artifactId>jedis</artifactId> <version>2.9.0</version> </dependency>
public class RedisTool { private static final String LOCK_SUCCESS = "OK"; private static final String SET_IF_NOT_EXIST = "NX"; private static final String SET_WITH_EXPIRE_TIME = "PX"; /** * 尝试获取分布式锁 * @param jedis Redis客户端 * @param lockKey 锁 * @param requestId 请求标识 * @param expireTime 超期时间 * @return 是否获取成功 */ public static boolean tryGetDistributedLock(Jedis jedis, String lockKey, String requestId, int expireTime) { String result = jedis.set(lockKey, requestId, SET_IF_NOT_EXIST, SET_WITH_EXPIRE_TIME, expireTime); if (LOCK_SUCCESS.equals(result)) { return true; } return false; } }
public class RedisTool { private static final Long RELEASE_SUCCESS = 1L; /** * 释放分布式锁 * @param jedis Redis客户端 * @param lockKey 锁 * @param requestId 请求标识 * @return 是否释放成功 */ public static boolean releaseDistributedLock(Jedis jedis, String lockKey, String requestId) { String script = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end"; Object result = jedis.eval(script, Collections.singletonList(lockKey), Collections.singletonList(requestId)); if (RELEASE_SUCCESS.equals(result)) { return true; } return false; } }
二:redisson使用:
<dependency> <groupId>org.redisson</groupId> <artifactId>redisson</artifactId> <version>3.5.4</version> </dependency>
@RestController public class StockController { @Autowired StockRepository stockRepository; ExecutorService executorService = Executors.newFixedThreadPool(10); @Autowired RedissonClient redissonClient; final static String id = "1"; @RequestMapping("/addStock") public void addStock() { RLock lock = redissonClient.getLock("redisson:lock:stock:" + id); for (int i = 0; i < 100; i++) { executorService.execute(() -> { lock.lock(); try { Stock stock = stockRepository.findOne(id); stock.setNumber(stock.getNumber() + 1); stockRepository.save(stock); } finally { lock.unlock(); } }); } } }
@RequestMapping("testReentrant") public void ReentrantLock() { RLock lock = redissonClient.getLock("fibonacci"); lock.lock(); try { int result = fibonacci(10); System.out.println(result); } finally { lock.unlock(); } } int fibonacci(int n) { RLock lock = redissonClient.getLock("fibonacci"); try { if (n <= 1) return n; else return fibonacci(n - 1) + fibonacci(n - 2); } finally { lock.unlock(); } }
笔记转移,由于在有道云的笔记转移,写的时间可能有点久,如果有错误的地方,请指正