Several implementation methods of Redis distributed lock

// Set the value of the key myKey to myValue, and the key expires after 10 secondsSET myKey myValue EX 10
// Set the value of the key myKey to myValue, and the key expires after 1000 milliseconds (1 second)SET myKey myValue PX 1000
// Specify the key expiration time, in seconds, and will be automatically deleted after expirationEXPIRE key_name second_num
// Specify the expiration time of the key, in milliseconds, and will be automatically deleted after expirationPEXPIRE key_name millisecond_num

// Return the key expiration timeTTL key_name 

SET key value	 //Set the value of the key key to valueSETNX key value	 //Only when the key key does not exist, set the value of the key to valueSETEX key seconds value	 //Set the value of the key key to value and the timeout is seconds secondsPSETEX key milliseconds value  //Set the value of the key key to value and the timeout is milliseconds milliseconds

public class SimpleRedisLock {
    private Jedis jedis;
    private String lockKey;

    public SimpleRedisLock(Jedis jedis, String lockKey) {
         = jedis;
         = lockKey;
    }
    public boolean tryLock() {
        Long result = (lockKey, "locked");
        if (result == 1) {
            (lockKey, 30); // Set expiration time            return true;
        }
        return false;
    }
    public void unlock() {
        (lockKey);
    }
}

// Use exampleJedis jedis = new Jedis("localhost");
SimpleRedisLock lock = new SimpleRedisLock(jedis, "order_lock");
try{
    if(()){
    // Business logic    }
} finally {
    ();
}

public class AtomicRedisLock {
    private Jedis jedis;
    private String lockKey;
    private String clientId;

    public SimpleRedisLock(Jedis jedis, String lockKey) {
         = jedis;
         = lockKey;
         = ().toString();
    }
    public boolean tryLock(int expireSeconds) {
        String result = (lockKey, clientId, ().nx().ex(expireSeconds));
        return "OK".equals(result);
    }
    public boolean unlock() {
        String script = "if ('get', KEYS[1]) == ARGV[1] then " +
                "return ('del', KEYS[1]) " +
                "else return 0 end";
        Object result = (script, (lockKey), (clientId));
        return (1L);
    }
}

// Use exampleJedis jedis = new Jedis("localhost");
AtomicRedisLock lock = new AtomicRedisLock(jedis, "payment_lock");
try{
    if((30)){
    // Business logic    }
} finally {
    ();
}

public class RedLock {
    pprivate List<Jedis> jedisList;
    private String lockKey;
    private String clientId;
    private int quorum;

    public RedLock(List<Jedis> jedisList, String lockKey) {
         = jedisList;
         = lockKey;
         = ().toString();
         = () / 2 + 1;
    }
    public boolean tryLock(int expireMillis) {
        long startTime = ();
        // Phase 1: Try to acquire most node locks        int successCount = 0;
        for (Jedis jedis : jedisList) {
            if (tryAcquire(jedis, expireMillis)) {
                successCount++;
            }
            if ((() - startTime) > expireMillis) {
                break;
            }
        }
        // Phase 2: Verify the validity of the lock        if (successCount >= quorum) {
            long validityTime = expireMillis - (() - startTime);
            return validityTime > 0;
        }
        // Stage 3: Release the acquired lock        for (Jedis jedis : jedisList) {
            release(jedis);
        }
        return false;
    }
    private boolean tryAcquire(Jedis jedis, long expireMillis) {
        try {
            String result = (lockKey, clientId, ().nx().px(expireMillis));
            return "OK".equals(result);
        } catch (Exception e) {
            return false;
        }
    }
    private void release(Jedis jedis) {
        String script = "if ('get', KEYS[1]) == ARGV[1] then " +
                "return ('del', KEYS[1]) else return 0 end";
        (script, (lockKey), (clientId));
    }
}

// Configure the Redisson clientConfig config = new Config();
().setAddress("redis://127.0.0.1:6379");
RedissonClient redisson = (config);
// Acquire the lock objectRLock lock = ("orderLock");
try {
    // Try to add lock, wait for up to 100 seconds, and automatically unlock 30 seconds after locking    boolean isLock = (100, 30, );
    if (isLock) {
        // Handle business    }
} finally {
    ();
}

// Close the client();

// Automatic renewal mechanism (Watchdog), Watchdog implementation principle (simplified version)private void renewExpiration() {
    Timeout task = (() -> {
        if ((...)){ // Check if the lock is still held            expireAsync(); // Renewal            renewExpiration(); // Recursive call        }
    }, internalLockLeaseTime / 3, );
}