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Snailclimb merged 1 commit into from
Sep 18, 2023
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Update java-concurrent-questions-02.md #2170

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4 changes: 2 additions & 2 deletions docs/java/concurrent/java-concurrent-questions-02.md
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Expand Up @@ -542,7 +542,7 @@ public class SynchronizedDemo {
相比`synchronized`，`ReentrantLock`增加了一些高级功能。主要来说主要有三点：

- **等待可中断** : `ReentrantLock`提供了一种能够中断等待锁的线程的机制，通过 `lock.lockInterruptibly()` 来实现这个机制。也就是说正在等待的线程可以选择放弃等待，改为处理其他事情。
- **可实现公平锁** : `ReentrantLock`可以指定是公平锁还是非公平锁。而`synchronized`只能是非公平锁。所谓的公平锁就是先等待的线程先获得锁。`ReentrantLock`默认情况是非公平的，可以通过 `ReentrantLock`类的`ReentrantLock(boolean fair)`构造方法来制定是否是公平的。
- **可实现公平锁** : `ReentrantLock`可以指定是公平锁还是非公平锁。而`synchronized`只能是非公平锁。所谓的公平锁就是先等待的线程先获得锁。`ReentrantLock`默认情况是非公平的，可以通过 `ReentrantLock`类的`ReentrantLock(boolean fair)`构造方法来指定是否是公平的。
- **可实现选择性通知（锁可以绑定多个条件）**: `synchronized`关键字与`wait()`和`notify()`/`notifyAll()`方法相结合可以实现等待/通知机制。`ReentrantLock`类当然也可以实现，但是需要借助于`Condition`接口与`newCondition()`方法。

如果你想使用上述功能，那么选择 `ReentrantLock` 是一个不错的选择。
Expand Down Expand Up @@ -707,4 +707,4 @@ Atomic 原子类部分的内容我单独写了一篇文章来总结：[Atomic
- 理解 Java 中的 ThreadLocal - 技术小黑屋：https://droidyue.com/blog/2016/03/13/learning-threadlocal-in-java/
- ThreadLocal (Java Platform SE 8 ) - Oracle Help Center：https://docs.oracle.com/javase/8/docs/api/java/lang/ThreadLocal.html

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