How Java timestamps are obtained

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Gets the current time stamp

Method one System.currenttimemillis ();//Method two Calendar.getinstance (). Gettimeinmillis ();//Method three new Date (). GetTime ();

Get current time

SimpleDateFormat df = new SimpleDateFormat ("Yyyy-mm-dd HH:mm:ss");//Set date format string day = Df.format (new date ());//new Date () to get the current system time, or to use the current timestamp

Get time stamp three ways to perform efficiency comparisons:

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 Curr        Enttime=calendar.getinstance (). Gettimeinmillis (); }} public static void TestDate (long times) {for (int i=0;i<times;i++) {long CurrEnttime=new Date (). GetTime (); }    } }

Execution Result:

133

2372

137

Calendar.getinstance (). Gettimeinmillis () This is the slowest, because it takes more time for the Canlendar to handle time zone problems.

How Java timestamps are obtained