Gets the current system time in Java, and converts the format to the string, or to the number of seconds, days, and so on integer

Convert into seconds

The date class has a gettime () that can swap back the number of seconds, for example:

 Public class datetosecond{publicstaticvoidnew  Date ( System.currenttimemillis ()); System.out.println (Date.gettime ());}}

Convert to string format

I. Get the current system time and date and format the output:

Import java.util.Date; Import Java.text.SimpleDateFormat;  Public class nowstring {publicstaticvoidnew SimpleDateFormat (" Yyyy-mm-dd HH:mm:ss "); // Set Date format System.out.println (Df.format (new Date ())); // new Date () to get the current system time }}

Two. The date in the database is only output in the form of year-month-day, which can be used in two ways:

1. CONVERT () Convert function:

String sqlst = "SELECT CONVERT (varchar), bookdate,126) as convertbookdate from RoomBook where bookdate between ' 2007-4-1 0 ' and ' 2007-4-25 '; System.out.println (rs.getstring ("convertbookdate"));

2, the use of SimpleDateFormat class:

To enter two Java packages first:

Import Java.util.Date;
Import Java.text.SimpleDateFormat;

And then:

Define date format: SimpleDateFormat SDF = new SimpleDateFormat (YY-MM-DD);

The SQL statement is: String sqlstr = "Select Bookdate from RoomBook where bookdate between ' 2007-4-10 ' and ' 2007-4-25 '";

Output:

System.out.println (Df.format (Rs.getdate ("bookdate"));

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Get each event domain separately

Importjava.util.Date;ImportJava.util.Calendar;ImportJava.text.SimpleDateFormat; Public classtestdate{ Public Static voidMain (string[] args) {Date now=NewDate (); SimpleDateFormat DateFormat=NewSimpleDateFormat ("Yyyy/mm/dd HH:mm:ss");//easy to modify date formatString hehe=Dateformat.format (now); SYSTEM.OUT.PRINTLN (hehe); Calendar C= Calendar.getinstance ();//can be modified individually for each time domain intYear =C.get (calendar.year);intmonth =C.get (calendar.month);intDate =C.get (calendar.date);inthour =C.get (calendar.hour_of_day);intminute =C.get (calendar.minute);intSecond =C.get (Calendar.second); System.out.println ( Year+ "/" + month + "/" + Date + "" +hour + ":" +minute + ":" +second); } }

Sometimes you convert a string of time to a date type, and you can convert the time string you just got to date type in the following way.

SimpleDateFormat sdf=New SimpleDateFormat ("Yyyy-mm-dd"); java.util.Datetime =null; Try {time = Sdf.parse (Sdf.format (newcatch  (ParseException e) {E.printstacktrace ();}

Gets the current system time in Java, and converts the format to the string, or to the number of seconds, days, and so on integer