//方法 一
System.currentTimeMillis();
//方法 二
Calendar.getInstance().getTimeInMillis();
//方法 三
new Date().getTime();

SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//设置日期格式
String date = df.format(new Date());// new Date()为获取当前系统时间，也可使用当前时间戳

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 188for(int i=0;i<times;i++){long currentTime=System.currentTimeMillis();}}public static void testCalander(long times){//use 6299for(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();}}}

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