问题描述
在Java中，如果变量的大小小于或等于32位，则赋值是原子的，但如果大于32位则不是。
In Java, assignment is atomic if the size of the variable is less than or equal to 32 bits but is not if more than 32 bits.
什么（volatile / synchronized）在双重或长期分配的情况下使用会更有效吗？
What (volatile/synchronized) would be more efficient to use in case of double or long assignment?
赞，
volatile double x = y;
synchronized不适用于原始参数。在这种情况下如何使用synchronized？当然我不想锁定我的类，所以不应该使用这个。
synchronized is not applicable with primitive argument. How do I use synchronized in this case? Of course I don't want to lock my class, so this should not be used.
推荐答案
如果你发现对象本身的锁定太重，那么同步就是要走的路。在Java 1.5之前，volatile可能是一个不错的选择，但是现在volatile可以通过在赋值发生的方法上强制执行指令来产生非常大的影响。创建一个单独的对象（ private final Object X_LOCK = new Object（）; ）并在设置或获取该double的值时对其进行同步。这将为您提供对锁定的精细控制，这似乎是您所需要的。
If you find locking on the object itself too heavy, then synchronized is the way to go. Prior to Java 1.5 volatile may have been a good choice, but now volatile can have a very large impact by forcing instruction ordering on the method where the assignment happens. Create a separate object (private final Object X_LOCK = new Object();) and synchronize on it when setting or getting the value of that double. This will give you a fine level of control over the locking, which it seems that you need.
在新的并发包中有更多选项，例如AtomicReference，它可能是如果你真的需要避免同步，那么它是volatile的一个很好的替代品。
In the new concurrency package there are more options, such as AtomicReference which may be a good replacement for volatile if you really need to avoid synchronization.
这篇关于原始类型的易失性或同步？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！