java如何使用运行时在一秒钟内退出循环？

Question

如何使用Runtime在一秒钟内退出循环？ 我想用这个密码

public class test {
    public static void main(String[] args) {
    Runtime runtime = Runtime.getRuntime();
    long usedMemory = runtime.totalMemory()-runtime.freeMemory();
    int mbytes = (int) usedMemory/1000; // Used memory (Mbytes)
    String str="a";

        while (somthing < one second ) {


       }
}

Answer 1

 long startTime = System.currentTimeMillis();
 while((System.currentTimeMillis()-startTime)<1000){
// Your task goes here
}

Answer 2

好的，要做到这一点，你需要记录开始时间，然后将其与当前时间进行比较

    long start = System.currentTimeMillis();
    String str="a";
    while (true) {
        long now = System.currentTimeMillis();
        if (now - start > 1000)
             break;

        // do your stuff
        str=str + "a"; 
    }

    System.out.println (str);

上面的代码可能会花费更多的时间来完成你想做的事情

Answer 3

long startTime = System.currentTimeMillis();

while((System.currentTimeMillis()-startTime)<=1000){
     str=str + "a"; 
}

Answer 4

我认为，如果你真的不需要使用Runtime，你可以使用类似的东西

public class test {
    public static void main(String[] args) {
    long startTime = System.currentTimeMillis();
    long currentTime = System.currentTimeMillis();
    long usedMemory = runtime.totalMemory()-runtime.freeMemory();
    int mbytes = (int) usedMemory/1000; // Used memory (Mbytes)
    String str="a";

    while (currentTime-startTime<1000) {
        currentTime = System.currentTimeMillis();
    }
}

Answer 5

在while循环中编写代码。它将在1秒后退出循环

long start = System.currentTimeMillis();
long end = start + 1000; //  1000 ms/sec
while (System.currentTimeMillis() < end)
{
    // Write your code here
}