Redisson实现Redis分布式锁的几种方式

目录

• Redis几种架构
• 普通分布式锁

• 单机模式
• 哨兵模式
• 集群模式
• 总结

// 构造redisson实现分布式锁必要的Config
Config config = new Config();
config.useSingleServer().setAddress("redis://172.29.1.180:5379").setPassword("a123456").setDatabase(0);
// 构造RedissonClient
RedissonClient redissonClient = Redisson.create(config);
// 设置锁定资源名称
RLock disLock = redissonClient.getLock("DISLOCK");
boolean isLock;
try {
    //尝试获取分布式锁
    isLock = disLock.tryLock(500, 15000, TimeUnit.MILLISECONDS);
    if (isLock) {
        //TODO if get lock success, do something;
        Thread.sleep(15000);
    }
} catch (Exception e) {
} finally {
    // 无论如何, 最后都要解锁
    disLock.unlock();
}

172.29.1.180:5379> hgetall DISLOCK
1) "01a6d806-d282-4715-9bec-f51b9aa98110:1"
2) "1"

Config config = new Config();
config.useSentinelServers().addSentinelAddress(
        "redis://172.29.3.245:26378","redis://172.29.3.245:26379", "redis://172.29.3.245:26380")
        .setMasterName("mymaster")
        .setPassword("a123456").setDatabase(0);

Config config = new Config();
config.useClusterServers().addNodeAddress(
        "redis://172.29.3.245:6375","redis://172.29.3.245:6376", "redis://172.29.3.245:6377",
        "redis://172.29.3.245:6378","redis://172.29.3.245:6379", "redis://172.29.3.245:6380")
        .setPassword("a123456").setScanInterval(5000);

Config config1 = new Config();
config1.useSingleServer().setAddress("redis://172.29.1.180:5378")
        .setPassword("a123456").setDatabase(0);
RedissonClient redissonClient1 = Redisson.create(config1);
Config config2 = new Config();
config2.useSingleServer().setAddress("redis://172.29.1.180:5379")
        .setPassword("a123456").setDatabase(0);
RedissonClient redissonClient2 = Redisson.create(config2);
Config config3 = new Config();
config3.useSingleServer().setAddress("redis://172.29.1.180:5380")
        .setPassword("a123456").setDatabase(0);
RedissonClient redissonClient3 = Redisson.create(config3);
String resourceName = "REDLOCK";
RLock lock1 = redissonClient1.getLock(resourceName);
RLock lock2 = redissonClient2.getLock(resourceName);
RLock lock3 = redissonClient3.getLock(resourceName);
RedissonRedLock redLock = new RedissonRedLock(lock1, lock2, lock3);
boolean isLock;
try {
    isLock = redLock.tryLock(500, 30000, TimeUnit.MILLISECONDS);
    System.out.println("isLock = "+isLock);
    if (isLock) {
        //TODO if get lock success, do something;
        Thread.sleep(30000);
    }
} catch (Exception e) {
} finally {
    // 无论如何, 最后都要解锁
    System.out.println("");
    redLock.unlock();
}

public boolean tryLock(long waitTime, long leaseTime, TimeUnit unit) throws InterruptedException {
    // 实现要点之允许加锁失败节点限制
    int failedLocksLimit = failedLocksLimit();
    List<RLock> acquiredLocks = new ArrayList<RLock>(locks.size());
    // 实现要点之遍历所有节点通过EVAL命令执行lua加锁
    for (ListIterator<RLock> iterator = locks.listIterator(); iterator.hasNext();) {
        RLock lock = iterator.next();
        boolean lockAcquired;
        try {
            // 对节点尝试加锁
            lockAcquired = lock.tryLock(awaitTime, newLeaseTime, TimeUnit.MILLISECONDS);
        } catch (RedisConnectionClosedException|RedisResponseTimeoutException e) {
            // 如果抛出这类异常，为了防止加锁成功，但是响应失败，需要解锁
            unlockInner(Arrays.asList(lock));
            lockAcquired = false;
        } catch (Exception e) {
            // 抛出异常表示获取锁失败
            lockAcquired = false;
        }
        if (lockAcquired) {
            // 成功获取锁集合
            acquiredLocks.add(lock);
        } else {
            // 如果达到了允许加锁失败节点限制，那么break，即此次Redlock加锁失败
            if (locks.size() - acquiredLocks.size() == failedLocksLimit()) {
                break;
            }               
        }
    }
    return true;
}