执行循环需要多长时间？ [英] How much time does it take to execute a loop?

问题描述

有没有办法知道在java中执行循环需要多少秒？

Is there any way to know how many seconds does it take a loop to execute in java?

例如：

for(int i=0; i < 1000000; i++) {

//Do some difficult task goes in here

}

它不必是100％准确，但它只是想知道可能需要多长时间。里面的算法是某种写入.txt文件的密钥生成器。我希望它甚至需要几分钟，所以对于我的第一次测试我想计算秒数。

It does not have to be accurate 100%, but its just to have an idea of how long it could take. The algorithm inside is some kind of key generator that writes to a .txt file. I expect it to take even a few mins, so for my first test i want to count the seconds.

推荐答案

在这里你可以试试这个：

Here you can try this:

long startTime = System.currentTimeMillis();
long endTime = 0;

    for(int i=0; i < 1000000; i++) {

    //Something

    }

endTime = System.currentTimeMillis();

long timeneeded =  ((startTime - endTime) /1000);

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