RLock lock = redisson.getLock("anyLock");
// 嘗試加鎖，最多等待100秒，上鎖以后10秒自動解鎖
boolean res = lock.tryLock(100, 10, TimeUnit.SECONDS);
if (res) {
   try {
     ...
   } finally {
       lock.unlock();
   }
}

/**
 * 獲取鎖
 * @param waitTime  嘗試獲取鎖的最大等待時間，超過這個值，則認為獲取鎖失敗
 * @param leaseTime 鎖的持有時間,超過這個時間鎖會自動失效（值應設置為大于業(yè)務處理的時間，確保在鎖有效期內業(yè)務能處理完）
 * @param unit 時間單位
 * @return 獲取鎖成功返回true，失敗返回false
 */
@Override
public boolean tryLock(long waitTime, long leaseTime, TimeUnit unit) throws InterruptedException {
    long time = unit.toMillis(waitTime);
    long current = System.currentTimeMillis();// 當前時間
    long threadId = Thread.currentThread().getId();// 當前線程id
 
    // 嘗試加鎖，加鎖成功返回null，失敗返回鎖的剩余超時時間
    Long ttl = tryAcquire(waitTime, leaseTime, unit, threadId);
    // 獲取鎖成功
    if (ttl == null) {
        return true;
    }
 
    // time小于0代表此時已經超過獲取鎖的等待時間，直接返回false
    time -= System.currentTimeMillis() - current;
    if (time <= 0) {
        // 沒看懂這個方法，里面里面空運行，有知道的大神還請不吝賜教
        acquireFailed(waitTime, unit, threadId);
        return false;
    }
    
    current = System.currentTimeMillis();
    CompletableFuture<RedissonLockEntry> subscribeFuture = subscribe(threadId);
    try {
        subscribeFuture.get(time, TimeUnit.MILLISECONDS);
    } catch (TimeoutException e) {
        if (!subscribeFuture.cancel(false)) {
            subscribeFuture.whenComplete((res, ex) -> {
                // 出現異常，取消訂閱
                if (ex == null) {
                    unsubscribe(res, threadId);
                }
            });
        }
        acquireFailed(waitTime, unit, threadId);
        return false;
    } catch (ExecutionException e) {
        acquireFailed(waitTime, unit, threadId);
        return false;
    }
 
    try {
        // 判斷是否超時（超過了waitTime）
        time -= System.currentTimeMillis() - current;
        if (time <= 0) {
            acquireFailed(waitTime, unit, threadId);
            return false;
        }
    
        while (true) {
            // 再次獲取鎖，成功則返回
            long currentTime = System.currentTimeMillis();
            ttl = tryAcquire(waitTime, leaseTime, unit, threadId);
            // lock acquired
            if (ttl == null) {
                return true;
            }
 
            time -= System.currentTimeMillis() - currentTime;
            if (time <= 0) {
                acquireFailed(waitTime, unit, threadId);
                return false;
            }
 
            // 阻塞等待信號量喚醒或者超時，接收到訂閱時喚醒
            // 使用的是Semaphore#tryAcquire()
            currentTime = System.currentTimeMillis();
            if (ttl >= 0 && ttl < time) {
                commandExecutor.getNow(subscribeFuture).getLatch().tryAcquire(ttl, TimeUnit.MILLISECONDS);
            } else {
                commandExecutor.getNow(subscribeFuture).getLatch().tryAcquire(time, TimeUnit.MILLISECONDS);
            }
 
            time -= System.currentTimeMillis() - currentTime;
            if (time <= 0) {
                acquireFailed(waitTime, unit, threadId);
                return false;
            }
        }
    } finally {
        // 因為是同步操作，所以無論加鎖成功或失敗，都取消訂閱
        unsubscribe(commandExecutor.getNow(subscribeFuture), threadId);
    }
//        return get(tryLockAsync(waitTime, leaseTime, unit));
}

private Long tryAcquire(long waitTime, long leaseTime, TimeUnit unit, long threadId) {
    return get(tryAcquireAsync(waitTime, leaseTime, unit, threadId));
}
 
private <T> RFuture<Long> tryAcquireAsync(long waitTime, long leaseTime, TimeUnit unit, long threadId) {
    RFuture<Long> ttlRemainingFuture;
    if (leaseTime > 0) {
        // 調用lua腳本，嘗試加鎖
        ttlRemainingFuture = tryLockInnerAsync(waitTime, leaseTime, unit, threadId, RedisCommands.EVAL_LONG);
    } else {
        // 這里的if、else的區(qū)別就在于，如果沒有設置leaseTime，就使用默認的internalLockLeaseTime（默認30秒）
        ttlRemainingFuture = tryLockInnerAsync(waitTime, internalLockLeaseTime,
                TimeUnit.MILLISECONDS, threadId, RedisCommands.EVAL_LONG);
    }
    CompletionStage<Long> f = ttlRemainingFuture.thenApply(ttlRemaining -> {
        // lock acquired
        // 如果ttlRemaining為空，也就是tryLockInnerAsync方法中的lua執(zhí)行結果返回空，證明獲取鎖成功
        if (ttlRemaining == null) {
            if (leaseTime > 0) {
                internalLockLeaseTime = unit.toMillis(leaseTime);
            } else {
                // 如果沒有設置鎖的持有時間（leaseTime），則啟動看門狗，定時給鎖續(xù)期，防止業(yè)務邏輯未執(zhí)行完成鎖就過期了
                scheduleExpirationRenewal(threadId);
            }
        }
        return ttlRemaining;
    });
    return new CompletableFutureWrapper<>(f);
}

// RedissonLock#tryLockInnerAsync
<T> RFuture<T> tryLockInnerAsync(long waitTime, long leaseTime, TimeUnit unit, long threadId, RedisStrictCommand<T> command) {
    return evalWriteAsync(getRawName(), LongCodec.INSTANCE, command,
            "if (redis.call('exists', KEYS[1]) == 0) then " +
                    "redis.call('hincrby', KEYS[1], ARGV[2], 1); " +
                    "redis.call('pexpire', KEYS[1], ARGV[1]); " +
                    "return nil; " +
                    "end; " +
                    "if (redis.call('hexists', KEYS[1], ARGV[2]) == 1) then " +
                    "redis.call('hincrby', KEYS[1], ARGV[2], 1); " +
                    "redis.call('pexpire', KEYS[1], ARGV[1]); " +
                    "return nil; " +
                    "end; " +
                    "return redis.call('pttl', KEYS[1]);",
            Collections.singletonList(getRawName()), unit.toMillis(leaseTime), getLockName(threadId));
}

if (ttl >= 0 && ttl < time) {
    commandExecutor.getNow(subscribeFuture).getLatch().tryAcquire(ttl, TimeUnit.MILLISECONDS);
} else {
    commandExecutor.getNow(subscribeFuture).getLatch().tryAcquire(time, TimeUnit.MILLISECONDS);
}

// LockPubSub#onMessage
protected void onMessage(RedissonLockEntry value, Long message) {
    // 普通的解鎖走的是這個
    if (message.equals(UNLOCK_MESSAGE)) {
        Runnable runnableToExecute = value.getListeners().poll();
        if (runnableToExecute != null) {
            runnableToExecute.run();
        }
        // 這里就是喚醒信號量的地方
        value.getLatch().release();
    // 這個是讀寫鎖用的
    } else if (message.equals(READ_UNLOCK_MESSAGE)) {
        while (true) {
            Runnable runnableToExecute = value.getListeners().poll();
            if (runnableToExecute == null) {
                break;
            }
            runnableToExecute.run();
        }
 
        value.getLatch().release(value.getLatch().getQueueLength());
    }
}

// RedissonLock#unlock
// RedissonBaseLock#unlockAsync(long threadId)
public RFuture<Void> unlockAsync(long threadId) {
    // 調用lua解鎖
    RFuture<Boolean> future = unlockInnerAsync(threadId);
 
    CompletionStage<Void> f = future.handle((opStatus, e) -> {
        // 取消看門狗
        cancelExpirationRenewal(threadId);
 
        if (e != null) {
            throw new CompletionException(e);
        }
        if (opStatus == null) {
            IllegalMonitorStateException cause = new IllegalMonitorStateException("attempt to unlock lock, not locked by current thread by node id: "
                    + id + " thread-id: " + threadId);
            throw new CompletionException(cause);
        }
 
        return null;
    });
 
    return new CompletableFutureWrapper<>(f);
}

// RedissonLock#unlockInnerAsync
protected RFuture<Boolean> unlockInnerAsync(long threadId) {
    return evalWriteAsync(getRawName(), LongCodec.INSTANCE, RedisCommands.EVAL_BOOLEAN,
            "if (redis.call('hexists', KEYS[1], ARGV[3]) == 0) then " +
                    "return nil;" +
                    "end; " +
                    "local counter = redis.call('hincrby', KEYS[1], ARGV[3], -1); " +
                    "if (counter > 0) then " +
                    "redis.call('pexpire', KEYS[1], ARGV[2]); " +
                    "return 0; " +
                    "else " +
                    "redis.call('del', KEYS[1]); " +
                    "redis.call('publish', KEYS[2], ARGV[1]); " +
                    "return 1; " +
                    "end; " +
                    "return nil;",
            Arrays.asList(getRawName(), getChannelName()), LockPubSub.UNLOCK_MESSAGE, internalLockLeaseTime, getLockName(threadId));
}

// RedissonLock#tryAcquireAsync
// RedissonBaseLock#scheduleExpirationRenewal
protected void scheduleExpirationRenewal(long threadId) {
    // 創(chuàng)建ExpirationEntry，并放入EXPIRATION_RENEWAL_MAP中，下面的renewExpiration()方法會從map中再拿出來用
    ExpirationEntry entry = new ExpirationEntry();
    ExpirationEntry oldEntry = EXPIRATION_RENEWAL_MAP.putIfAbsent(getEntryName(), entry);
    if (oldEntry != null) {
        oldEntry.addThreadId(threadId);
    } else {
        entry.addThreadId(threadId);
        try {
            // 看門狗的具體邏輯
            renewExpiration();
        } finally {
            // 如果線程被中斷了，就取消看門狗
            if (Thread.currentThread().isInterrupted()) {
                // 取消看門狗
                cancelExpirationRenewal(threadId);
            }
        }
    }
}

private void renewExpiration() {
    ExpirationEntry ee = EXPIRATION_RENEWAL_MAP.get(getEntryName());
    if (ee == null) {
        return;
    }
 
    // 創(chuàng)建延時任務，延時時間是internalLockLeaseTime / 3
    Timeout task = commandExecutor.getConnectionManager().newTimeout(new TimerTask() {
        @Override
        public void run(Timeout timeout) throws Exception {
            ExpirationEntry ent = EXPIRATION_RENEWAL_MAP.get(getEntryName());
            if (ent == null) {
                return;
            }
            Long threadId = ent.getFirstThreadId();
            if (threadId == null) {
                return;
            }
 
            // lua腳本判斷，如果鎖存在，則續(xù)期并返回true，不存在則返回false
            CompletionStage<Boolean> future = renewExpirationAsync(threadId);
            future.whenComplete((res, e) -> {
                if (e != null) {
                    log.error("Can't update lock " + getRawName() + " expiration", e);
                    EXPIRATION_RENEWAL_MAP.remove(getEntryName());
                    return;
                }
                
                if (res) {
                    // 鎖續(xù)期成功，則再啟動一個延時任務，繼續(xù)監(jiān)測
                    renewExpiration();
                } else {
                    // 取消看門狗
                    cancelExpirationRenewal(null);
                }
            });
        }
    }, internalLockLeaseTime / 3, TimeUnit.MILLISECONDS);
    
    ee.setTimeout(task);
}