Java System.currentTimeMillis()

import java.text.SimpleDateFormat;
import java.util.Date;

public class Test {
    
    
    public static void main(String[] args) throws Exception{
    
    
        //自1970/01/01 00:00:00 000到现在的时间所经历的毫秒数
        long l = System.currentTimeMillis();
        System.out.println(l);
        long l1 = System.currentTimeMillis();
        Test.print();
        long l2 = System.currentTimeMillis();
        System.out.println(l2-l1);//循环10000000只需要2毫秒
    }
    public static void print(){
    
    
        for(int i=0;i<=10000000;i++){
    
    
//            System.out.println(i);
        }
    }
}