的AtomicBoolean VS synchronized块，什么区别 [英] AtomicBoolean vs Synchronized block, whats the difference

问题描述

我想了解两者的区别如下code块

I am trying to understand the difference between the two following code blocks

AtomicBoolean ab = new AtomicBoolean(false);  

using the following to get and set state. .
ab.get();
ab.set(X);

vs. 

private boolean ab = false;
private final Object myboollock = new Ojbect();

public void setAB(boolean state)
{
    synchronized(myboollock)
     {
          ab = state;
     }
}

public boolean getAB()
{
 synchronized(myboollock)
 {
         return ab;
 }
}

我需要线程保护一个布尔值，这是所有，并有
在过去使用的后一种方法，但想开始使用原子
对象，（如果）他们是安全的？

I need to thread protect a boolean, that is all, and have in the past used the later method, but would like to start to use Atomic objects, (if ) they are safe?,

推荐答案

有一些细微的差别，但是从两个code段外的行为类似看出：如果调用设置方法，这种变化将是其他线程调用可见 GET 其后。

There are a few subtle differences but seen from the outside the two code snippets behave similarly: if you call the set method, the change will be visible to other threads calling get subsequently.

的主要区别是：

• 性能：根据争的水平，你可以用同步或的AtomicBoolean
  
• 原子性：如果在某个阶段你想要做的不仅仅是设置布尔值，同步块将允许您原子加指令，但的AtomicBoolean 不会

• performance: depending on the level of contention, you may get better performance with synchronized or AtomicBoolean
• atomicity: if at some stage you want to do more than just setting the boolean value, a synchronized block will allow you to add instructions atomically but AtomicBoolean won't

这篇关于的AtomicBoolean VS synchronized块，什么区别的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！