Spring boot 中 Redis 实现简易分布式锁

Demo.java · 362 B · Java Raw

1	DistributedLockParam lockParam = null;
2	try {
3	lockParam = new DistributedLockParam("test:lock:key");
4	boolean lockOk = distributedLock.lock(lockParam);
5	if (!lockOk) {
6	return new Result().error("系统繁忙，请稍候重试");
7	}
8	// 执行业务逻辑
9	} finally {
10	// 最后强制解锁
11	if (lockParam != null) {
12	distributedLock.unlock(lockParam);
13	}
14	}

DistributedLock.java · 364 B · Java Raw

1	/**
2	* 分布式锁
3	*/
4	public interface DistributedLock {
5
6	/**
7	* 加锁
8	*
9	* @param param 加锁参数
10	* @return 加锁是否成功
11	*/
12	boolean lock(DistributedLockParam param);
13
14	/**
15	* 解锁
16	*
17	* @param param 加锁参数
18	* @return 解锁是否成功
19	*/
20	boolean unlock(DistributedLockParam param);
21	}

RedisDistributedLockImpl.jav · 2.3 KiB · Text Raw

import lombok.RequiredArgsConstructor; import org.apache.commons.lang3.StringUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.data.redis.core.RedisTemplate; import org.springframework.data.redis.core.script.DefaultRedisScript; import org.springframework.data.redis.core.script.RedisScript; import org.springframework.stereotype.Service; import java.util.Collections; import java.util.concurrent.TimeUnit; /** * Redis Lock **/ @Service @RequiredArgsConstructor public class RedisDistributedLockImpl implements DistributedLock { private static final Logger log = LoggerFactory.getLogger(RedisDistributedLockImpl.class); private static final String UNLOCK_SCRIPT = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end"; private static final Long UNLOCK_SUCCESS = 1L; private final RedisTemplate<String, String> redisTemplate; @Override @SuppressWarnings({"BusyWait", "java:S2142"}) public boolean lock(DistributedLockParam param) { final long tryLockEndTime = param.getTryLockTime() + System.currentTimeMillis(); while (true) { //判断是否超过了，尝试获取锁的时间 if (System.currentTimeMillis() > tryLockEndTime) { return false; } // 尝试获取锁 Boolean ok = redisTemplate.opsForValue().setIfAbsent(param.getKey(), param.getValue(), param.getHoldLockTime(), TimeUnit.MILLISECONDS); if (Boolean.TRUE.equals(ok)) { return true; } try { //获得锁失败，休眠50毫秒再去尝试获得锁,避免一直请求redis，导致redis cpu飙升 Thread.sleep(50); } catch (InterruptedException e) { log.info(e.getMessage()); } } } @Override public boolean unlock(DistributedLockParam param) { if (StringUtils.isBlank(param.getKey()) || StringUtils.isBlank(param.getValue())) { return false; } RedisScript<Long> redisScript = new DefaultRedisScript<>(UNLOCK_SCRIPT, Long.class); Long result = redisTemplate.execute(redisScript, Collections.singletonList(param.getKey()), param.getValue()); return UNLOCK_SUCCESS.equals(result); } }

1	import lombok.RequiredArgsConstructor;
2	import org.apache.commons.lang3.StringUtils;
3	import org.slf4j.Logger;
4	import org.slf4j.LoggerFactory;
5	import org.springframework.data.redis.core.RedisTemplate;
6	import org.springframework.data.redis.core.script.DefaultRedisScript;
7	import org.springframework.data.redis.core.script.RedisScript;
8	import org.springframework.stereotype.Service;
9
10	import java.util.Collections;
11	import java.util.concurrent.TimeUnit;
12
13	/**
14	* Redis Lock
15	**/
16	@Service
17	@RequiredArgsConstructor
18	public class RedisDistributedLockImpl implements DistributedLock {
19
20	private static final Logger log = LoggerFactory.getLogger(RedisDistributedLockImpl.class);
21
22	private static final String UNLOCK_SCRIPT = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end";
23	private static final Long UNLOCK_SUCCESS = 1L;
24
25	private final RedisTemplate<String, String> redisTemplate;
26
27	@Override
28	@SuppressWarnings({"BusyWait", "java:S2142"})
29	public boolean lock(DistributedLockParam param) {
30	final long tryLockEndTime = param.getTryLockTime() + System.currentTimeMillis();
31	while (true) {
32	//判断是否超过了，尝试获取锁的时间
33	if (System.currentTimeMillis() > tryLockEndTime) {
34	return false;
35	}
36
37	// 尝试获取锁
38	Boolean ok = redisTemplate.opsForValue().setIfAbsent(param.getKey(), param.getValue(), param.getHoldLockTime(), TimeUnit.MILLISECONDS);
39	if (Boolean.TRUE.equals(ok)) {
40	return true;
41	}
42
43	try {
44	//获得锁失败，休眠50毫秒再去尝试获得锁,避免一直请求redis，导致redis cpu飙升
45	Thread.sleep(50);
46	} catch (InterruptedException e) {
47	log.info(e.getMessage());
48	}
49	}
50	}
51
52	@Override
53	public boolean unlock(DistributedLockParam param) {
54	if (StringUtils.isBlank(param.getKey()) \|\| StringUtils.isBlank(param.getValue())) {
55	return false;
56	}
57	RedisScript<Long> redisScript = new DefaultRedisScript<>(UNLOCK_SCRIPT, Long.class);
58	Long result = redisTemplate.execute(redisScript, Collections.singletonList(param.getKey()), param.getValue());
59	return UNLOCK_SUCCESS.equals(result);
60	}
61	}