Java获取当前时间戳案例详解

//方法 一

System.currentTimeMillis();

//方法 二

Calendar.getInstance().getTimeInMillis();

//方法 三

new Date().getTime();

import java.util.Calendar;

import java.util.Date;

public class TimeTest {

     private static long _TEN_THOUSAND= 10000 ;

     public static void main(String[] args) {

         long times= 1000 *_TEN_THOUSAND;

         long t1=System.currentTimeMillis();

         testSystem(times);

         long t2=System.currentTimeMillis();

         System.out.println(t2-t1);

         testCalander(times);

         long t3=System.currentTimeMillis();

         System.out.println(t3-t2);

         testDate(times);

         long t4=System.currentTimeMillis();

         System.out.println(t4-t3);

     }

     public static void testSystem( long times){ //use 188

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

             long currentTime=System.currentTimeMillis();

         }

     }

     public static void testCalander( long times){ //use 6299

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

             long currentTime=Calendar.getInstance().getTimeInMillis();

         }

     }

     public static void testDate( long times){

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

             long currentTime= new Date().getTime();

         }

     }

}