Redis的分布式锁如何使用和代码示例

<dependency>
    <groupId>redis.clients</groupId>
    <artifactId>jedis</artifactId>
    <version>3.7.0</version>
</dependency>

import redis.clients.jedis.Jedis;
import redis.clients.jedis.params.SetParams;
public class RedisDistributedLock {
    private final Jedis jedis;
    private final String lockKey;
    private final long expireTime;
    public RedisDistributedLock(Jedis jedis, String lockKey, long expireTime) {
        this.jedis = jedis;
        this.lockKey = lockKey;
        this.expireTime = expireTime;
    }
    public boolean acquireLock(String lockValue) {
        SetParams params = new SetParams().nx().px(expireTime);
        String result = jedis.set(lockKey, lockValue, params);
        return "OK".equals(result);
    }
    public boolean releaseLock(String lockValue) {
        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, 1, lockKey, lockValue);
        return "1".equals(result.toString());
    }
    public static void main(String[] args) {
        try (Jedis jedis = new Jedis("localhost", 6379)) {
            String lockKey = "myLock";
            String lockValue = "myUniqueValue";
            long expireTime = 30000; // 30 seconds
            RedisDistributedLock lock = new RedisDistributedLock(jedis, lockKey, expireTime);
            // Acquire lock
            if (lock.acquireLock(lockValue)) {
                System.out.println("Lock acquired!");
                // Do your critical section work here
                // Release lock
                if (lock.releaseLock(lockValue)) {
                    System.out.println("Lock released!");
                } else {
                    System.out.println("Failed to release lock!");
                }
            } else {
                System.out.println("Failed to acquire lock!");
            }
        }
    }
}

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.params.SetParams;
import java.util.Arrays;
import java.util.List;
import java.util.UUID;
public class RedisRedlock {
    private final List<JedisPool> jedisPools;
    private final long expireTime;
    private final long retryDelay;
    private final int retryCount;
    public RedisRedlock(List<JedisPool> jedisPools, long expireTime, long retryDelay, int retryCount) {
        this.jedisPools = jedisPools;
        this.expireTime = expireTime;
        this.retryDelay = retryDelay;
        this.retryCount = retryCount;
    }
    public String acquireLock(String lockKey) {
        String lockValue = UUID.randomUUID().toString();
        int n = jedisPools.size();
        int quorum = n / 2 + 1;
        for (int i = 0; i < retryCount; i++) {
            int count = 0;
            long startTime = System.currentTimeMillis();
            for (JedisPool pool : jedisPools) {
                try (Jedis jedis = pool.getResource()) {
                    SetParams params = new SetParams().nx().px(expireTime);
                    String result = jedis.set(lockKey, lockValue, params);
                    if ("OK".equals(result)) {
                        count++;
                    }
                }
            }
            long elapsedTime = System.currentTimeMillis() - startTime;
            if (count >= quorum && elapsedTime <= expireTime) {
                return lockValue;
            } else {
                for (JedisPool pool : jedisPools) {
                    try (Jedis jedis = pool.getResource()) {
                        if (lockValue.equals(jedis.get(lockKey))) {
                            jedis.del(lockKey);
                        }
                    }
                }
            }
            try {
                Thread.sleep(retryDelay);
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            }
        }
        return null;
    }
    public boolean releaseLock(String lockKey, String lockValue) {
        String script = "if redis.call('get', KEYS[1]) == ARGV[1] then " +
                        "return redis.call('del', KEYS[1]) " +
                        "else return 0 end";
        boolean success = false;
        for (JedisPool pool : jedisPools) {
            try (Jedis jedis = pool.getResource()) {
                Object result = jedis.eval(script, Arrays.asList(lockKey), Arrays.asList(lockValue));
                if ("1".equals(result.toString())) {
                    success = true;
                }
            }
        }
        return success;
    }
    public static void main(String[] args) {
        List<JedisPool> jedisPools = Arrays.asList(
                new JedisPool("localhost", 6379),
                new JedisPool("localhost", 6380),
                new JedisPool("localhost", 6381)
        );
        long expireTime = 30000; // 30 seconds
        long retryDelay = 200; // 200 milliseconds
        int retryCount = 3;
        RedisRedlock redlock = new RedisRedlock(jedisPools, expireTime, retryDelay, retryCount);
        String lockKey = "myLock";
        String lockValue = redlock.acquireLock(lockKey);
        if (lockValue != null) {
            System.out.println("Lock acquired!");
            // Do your critical section work here
            if (redlock.releaseLock(lockKey, lockValue)) {
                System.out.println("Lock released!");
            } else {
                System.out.println("Failed to release lock!");
            }
        } else {
            System.out.println("Failed to acquire lock!");
        }
    }
}