在循环内部或外部声明一个对象？

问题描述

以下代码段是否有任何性能损失？

Is there any performance penalty for the following code snippet?

for (int i=0; i<someValue; i++)
{
    Object o = someList.get(i);
    o.doSomething;
}

或者这段代码实际上更有意义吗？

Or does this code actually make more sense?

Object o;
for (int i=0; i<someValue; i++)
{
    o = someList.get(i);
    o.doSomething;
}

如果在字节码中这两个完全等价，那么显然第一种方法看起来更好在风格方面，但我想确保是这种情况。

If in byte code these two are totally equivalent then obviously the first method looks better in terms of style, but I want to make sure this is the case.

推荐答案

在今天的编译器中，没有。我在最小的范围内声明对象，因为它对下一个人来说更具可读性。

In today's compilers, no. I declare objects in the smallest scope I can, because it's a lot more readable for the next guy.

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