Example of a time class usage in Java Date,timestamp,dateformat

We will analyze the time-date class and the processing functions in Java itself.

A class related to the time date.

　　java.util.Date . Implements a class whose objects have time, date components.

　　Java.util.Calendar . An abstract class whose objects have time, date components.

　　java.sql.Date . Implements a class whose object has a date component.

　　Java.sql.Time . Implements a class whose objects have a time component.

　　Java.sql.Timestamp . Implements a class whose objects have a time-date component.

　　Java.text.DateFormat . An abstract class whose objects are formatted with a time date.

We generally use classes java.util.Date,java.util.Calendar,java.sql.Timestamp, Java.text.DateFormat Perform time-date operations because they have full time-date components and comprehensive formatting capabilities. It is worth noting that java.sql.Date does not have a time component, and java.sql.Time does not have a date component !

Here are some examples of usage

public static void Main (string[] args) {/*** shows the output type of each datetime component */java.sql.date sqldate = new Java.sql.Date ( System.currenttimemillis ()); System.out.println (Sqldate.tostring ()); Output result: 2015-06-25java.sql.time sqltime = new Java.sql.Time (System.currenttimemillis ()); System.out.println (Sqltime.tostring ()); Output result: 09:13:43java.sql.timestamp Sqltimestamp = new Java.sql.Timestamp (System.currenttimemillis ()); System.out.println (Sqltimestamp.tostring ()); Output result: 2015-06-25 09:13:43.561java.util.date utildate = new Java.util.Date (System.currenttimemillis ()); System.out.println (Utildate.tostring ()); Output result: Thu June 09:13:43 CST 2015java.util.calendar cl = java.util.Calendar.getInstance (); System.out.println (Cl.gettime (). toString ()); Output result: Thu June 09:13:43 CST 2015}

public static void Main (string[] args) {/** * java.sql.Timestamp usage, */@SuppressWarnings ("deprecation") Java.sql.Timestamp sqlTimestamp1 = new Java.sql.Timestamp (2015,6,25,9,13,43,561); Java.sql.Timestamp Sqltimestamp = New Java.sql.Timestamp (System.currenttimemillis ()); System.out.println (Sqltimestamp); Boolean isafter = Sqltimestamp.after (SQLTIMESTAMP1); System.out.println (isafter);    Falseboolean Isbefore = Sqltimestamp.before (SQLTIMESTAMP1); System.out.println (Isbefore);   true//is used to compare the length of two time points, in milliseconds long gettimes = Sqltimestamp.gettime (); System.out.println (gettimes);   Output: 1435196988250//convert String type to Timestamp type Java.sql.Timestamp SQLTIMESTAMP2 = java.sql.Timestamp.valueOf ("2015-06-25 09:48:16.524 "); System.out.println (SQLTIMESTAMP2);   Output: 2015-06-25 09:48:16.524}

public static void Main (string[] args) {/** * Java.text.SimpleDateFormat usage */simpledateformat df = new SimpleDateFormat (" Yyyy-mm-dd HH:mm:ss "); Timestamp now = new Timestamp (System.currenttimemillis ()); System.out.println (now); 2015-06-25 14:27:41.477string time = Df.format (now); System.out.println (time); 2015-06-25 14:27:41system.out.println (timestamp.valueof (time)); 2015-06-25 14:27:41.0date now1 = new Date (); System.out.println (now); 2015-06-25 14:27:41.477string time1 = Df.format (NOW1); System.out.println (TIME1); 2015-06-25 14:27:41system.out.println (timestamp.valueof (time1)); 2015-06-25 14:27:41.0}

public static void Main (string[] args) {/** * Java.util.Calendar usage */calendar calendar1 = calendar.getinstance (); System.out.println (CALENDAR1); java.util.gregoriancalendar[time=1435214975097,arefieldsset=true,//areallfieldsset=true,lenient=true,zone= Sun.util.calendar.zoneinfo[id= "Asia/shanghai",//offset=28800000,dstsavings=0,usedaylight=false,transitions=19, lastrule=null],//firstdayofweek=1,minimaldaysinfirstweek=1,era=1,year=2015,month=5,//WEEK_OF_YEAR=26,WEEK_OF_ month=4,day_of_month=25,day_of_year=176,day_of_week=5,day_of_week_in_month=4,//AM_PM=1,HOUR=2,HOUR_OF_DAY=14, minute=49,second=35,millisecond=97,zone_offset=28800000,dst_offset=0]//Get time Date date1 = Calendar1.gettime (); System.out.println (date1); Thu June 14:49:35 CST 2015system.out.println (Calendar1.getweeksinweekyear ()); 52system.out.println (Calendar1.get (calendar.day_of_month)); 25system.out.println (Calendar1.get (calendar.hour_of_day)); 14}

Example of a time class usage in Java Date,timestamp,dateformat