使用静态私有方法真的比实例私有方法更快/更好吗？ [英] Is using static private methods really faster/better than instance private methods?

问题描述

我要问的是在做这个之间是否有区别：

What I'm asking is whether there is a difference between doing this:

public Something importantBlMethod(SomethingElse arg) {
    if (convenienceCheckMethod(arg)) {
        // do important BL stuff
    }
}

private boolean convenienceCheckMethod(SomethingElse arg) {
    // validate something
}

b

public Something importantBlMethod(SomethingElse arg) {
    if (convenienceCheckMethod(arg)) {
        // do important BL stuff
    }
}

private static boolean convenienceCheckMethod(SomethingElse arg) {
    // validate something
}

我实际上使用选项1，因为它对我来说更自然。

I actually use option 1 as it seems more natural to me.

第一种和第二种方式之间的惯例/性能差异？

So is there a style/convention/performance difference between the first and the second way ?

谢谢，

如我在测试它的评论中所建议的，在我的基准测试中，动态方法更快。

As suggested in the comments I tested it, in my benchmarks the dynamic method is faster.

这是测试代码：

public class Tests {

    private final static int ITERATIONS = 100000;

    public static void main(String[] args) {
        final long start = new Date().getTime();

        final Service service = new Service();
        for (int i = 0; i < ITERATIONS; i++) {

            service.doImportantBlStuff(new SomeDto());
        }

        final long end = new Date().getTime();

        System.out.println("diff: " + (end - start) + " millis");
    }
}

这是服务代码：

public class Service {

    public void doImportantBlStuff(SomeDto dto) {

        if (checkStuffStatic(dto)) {

        }

        // if (checkStuff(dto)) {

        // }
    }

    private boolean checkStuff(SomeDto dto) {
        System.out.println("dynamic");
        return true;
    }

    private static boolean checkStuffStatic(SomeDto dto) {
        System.out.println("static");
        return true;
    }
}

对于100000次迭代，动态方法传递577ms，静态615ms。

For 100000 iterations the dynamic method passes for 577ms, the static 615ms.

但是对我来说这是不确定的，因为我不知道什么，什么时候编译器决定优化。

This however is inconclusive for me since I don't know what and when the compiler decides to optimize.

这是我想要找出的。

推荐答案

性能明显：可忽略。

经验法则是声明你的方法static，如果它不与它的类的任何成员交互。

The rule of thumb is to declare your method static if it doesn't interact with any members of its class.

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