Java get time and get date

java get milliseconds: System.currentTimeMillis ()

 Java gets nanoseconds: System.nanoTime () (used to get very accurate time, recommended!)

 java get the current date:

    GregorianCalendar date_1 = (GregorianCalendar) Calendar.getInstance ();

    java.sql.Date date_2 = new java.sql.Date (date_1.getTime (). getTime ());

 -------------------------------------------------- -------------------------------------

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.util.Calendar;

import java.util.Date;

      

public class DateTest {

    public static void main (String [] args) throws ParseException {

        Calendar now = Calendar.getInstance ();

        System.out.println ("Year:" + now.get (Calendar.YEAR));

        System.out.println ("Month:" + (now.get (Calendar.MONTH) + 1));

        System.out.println ("Day:" + now.get (Calendar.DAY_OF_MONTH));

        System.out.println ("When:" + now.get (Calendar.HOUR_OF_DAY));

        System.out.println ("Point:" + now.get (Calendar.MINUTE));

        System.out.println ("second:" + now.get (Calendar.SECOND));

        System.out.println ("Current time in milliseconds:" + now.getTimeInMillis ());

        System.out.println (now.getTime ());

  

        Date d = new Date ();

        System.out.println (d);

        SimpleDateFormat sdf = new SimpleDateFormat ("yyyy-MM-dd HH: mm: ss");

        // SimpleDateFormat sdf = new SimpleDateFormat ("yyyy / MM / dd HH: mm: ss");

        String dateNowStr = sdf.format (d);

        System.out.println ("Formatted date:" + dateNowStr);

          

        String str = "2012-08-20 17:52:07"; // It must be in the same format as defined above

        Date today = sdf.parse (str);

        System.out.println ("String converted to date:" + today);

    }

}

Output result:

Year: 2012

Month: 8

Day: 20

Hours: 17

Points: 53

Second: 46

Current time in milliseconds: 1345456426312

Mon Aug 20 17:53:46 CST 2012

Mon Aug 20 17:53:46 CST 2012

Date after formatting: 2012-08-20 17:53:46

String to date: Mon Aug 20 17:52:07 CST 2012

-------------------------------------------------- -------------------------------------

import java.text.DateFormat;

import java.text.ParsePosition;

import java.text.SimpleDateFormat;

import java.util.Calendar;

import java.util.Date;

import java.util.GregorianCalendar;

  

public class TimeTest {

    // Used to control global changes in the previous week, this week, and next week

    private int weeks = 0;

    private int MaxDate; // Maximum number of days in January

    private int MaxYear; // The maximum number of days in a year

    public static void main (String [] args) {

        TimeTest tt = new TimeTest ();

        System.out.println ("Get the date of the day:" + tt.getNowTime ("yyyy-MM-dd"));

        System.out.println ("Get this Monday's date:" + tt.getMondayOFWeek ());

        System.out.println ("Get the date of this Sunday:" + tt.getCurrentWeekday ());

        System.out.println ("Get the date of last Monday:" + tt.getPreviousWeekday ());

        System.out.println ("Get the date of last Sunday:" + tt.getPreviousWeekSunday ());

        System.out.println ("Get the next Monday date:" + tt.getNextMonday ());

        System.out.println ("Get the next Sunday:" + tt.getNextSunday ());

        System.out.println ("Get the date of the corresponding week Saturday:" + tt.getNowTime ("yyyy-MM-dd"));

        System.out.println ("Get the date of the first day of the month:" + tt.getFirstDayOfMonth ());

        System.out.println ("Get the date of the last day of the month:" + tt.getDefaultDay ());

        System.out.println ("Get the date of the first day of the previous month:" + tt.getPreviousMonthFirst ());

        System.out.println ("Get the date of the last day of the previous month:" + tt.getPreviousMonthEnd ());

        System.out.println ("Get the date of the first day of the next month:" + tt.getNextMonthFirst ());

        System.out.println ("Get the date of the last day of the next month:" + tt.getNextMonthEnd ());

        System.out.println ("Get how many days this year:" + tt.getMaxYear ());

        System.out.println ("Get the date of the first day of the year:" + tt.getCurrentYearFirst ());

        System.out.println ("Get the date of the last day of the year:" + tt.getCurrentYearEnd ());

        System.out.println ("Get the date of the first day of last year:" + tt.getPreviousYearFirst ());

        System.out.println ("Get the date of the last day of last year:" + tt.getPreviousYearEnd ());

        System.out.println ("Get the date of the first day of next year:" + tt.getNextYearFirst ());

        System.out.println ("Get the date of the last day of next year:" + tt.getNextYearEnd ());

        System.out.println ("Get the first day to the last day of the quarter:" + tt.getThisSeasonTime (11));

        System.out.println ("Get the number of days between two dates 2011-12-1 ~ 2012-7.29:" + TimeTest.getTwoDay ("2012-7-29", "2011-12-1"));

    }

      

      

    / **

        * Get the number of days between two days

        * /

    public static String getTwoDay (String sj1, String sj2) {

        SimpleDateFormat myFormatter = new SimpleDateFormat ("yyyy-MM-dd");

        long day = 0;

        try {

         java.util.Date date = myFormatter.parse (sj1);

         java.util.Date mydate = myFormatter.parse (sj2);

         day = (date.getTime ()-mydate.getTime ()) / (24 * 60 * 60 * 1000);

        } catch (Exception e) {

         return "";

        }

        return day + "";

    }

  

  

    / **

        * According to a date, return a string that is the day of the week

        * /

    public static String getWeek (String sdate) {

        // convert to time

        Date date = TimeTest.strToDate (sdate);

        Calendar c = Calendar.getInstance ();

        c.setTime (date);

        // int hour = c.get (Calendar.DAY_OF_WEEK);

        // The day of the week is stored in hour, the range is 1 ~ 7

        // 1 = Sunday 7 = Saturday, other analogies

        return new SimpleDateFormat ("EEEE"). format (c.getTime ());

    }

  

    / **

        * Convert short time format string to time yyyy-MM-dd

        * /

    public static Date strToDate (String strDate) {

        SimpleDateFormat formatter = new SimpleDateFormat ("yyyy-MM-dd");

        ParsePosition pos = new ParsePosition (0);

        Date strtodate = formatter.parse (strDate, pos);

        return strtodate;

    }

  

    / **

        * Number of days between two times

        * /

    public static long getDays (String date1, String date2) {

        if (date1 == null || date1.equals (""))

         return 0;

        if (date2 == null || date2.equals (""))

         return 0;

        // Convert to standard time

        SimpleDateFormat myFormatter = new SimpleDateFormat ("yyyy-MM-dd");

        java.util.Date date = null;

        java.util.Date mydate = null;

        try {

         date = myFormatter.parse (date1);

         mydate = myFormatter.parse (date2);

        } catch (Exception e) {

        }

        long day = (date.getTime ()-mydate.getTime ()) / (24 * 60 * 60 * 1000);

        return day;

    }

  

  

  

      

    // Calculate the last day of the month and return the string

    public String getDefaultDay () {

       String str = "";

       SimpleDateFormat sdf = new SimpleDateFormat ("yyyy-MM-dd");

  

       Calendar lastDate = Calendar.getInstance ();

       lastDate.set (Calendar.DATE, 1); // Set to the 1st of the current month

       lastDate.add (Calendar.MONTH, 1); // Add a month to become the 1st of the next month

       lastDate.add (Calendar.DATE, -1); // Subtract one day to become the last day of the month

         

       str = sdf.format (lastDate.getTime ());

       return str;

    }

      

    // The first day of last month

    public String getPreviousMonthFirst () {

       String str = "";

       SimpleDateFormat sdf = new SimpleDateFormat ("yyyy-MM-dd");

  

       Calendar lastDate = Calendar.getInstance ();

       lastDate.set (Calendar.DATE, 1); // Set to the 1st of the current month

       lastDate.add (Calendar.MONTH, -1); // Subtract one month, become the 1st of next month

       //lastDate.add(Calendar.DATE,-1);//Subtract one day to become the last day of the month

         

       str = sdf.format (lastDate.getTime ());

       return str;

    }

      

    // Get the first day of the month

    public String getFirstDayOfMonth () {

       String str = "";

       SimpleDateFormat sdf = new SimpleDateFormat ("yyyy-MM-dd");

  

       Calendar lastDate = Calendar.getInstance ();

       lastDate.set (Calendar.DATE, 1); // Set to the 1st of the current month

       str = sdf.format (lastDate.getTime ());

       return str;

    }

      

    // Get the date of this Sunday

    public String getCurrentWeekday () {

        weeks = 0;

        int mondayPlus = this.getMondayPlus ();

        GregorianCalendar currentDate = new GregorianCalendar ();

        currentDate.add (GregorianCalendar.DATE, mondayPlus + 6);

        Date monday = currentDate.getTime ();

          

        DateFormat df = DateFormat.getDateInstance ();

        String preMonday = df.format (monday);

        return preMonday;

    }

      

      

    // Get the time of day

    public String getNowTime (String dateformat) {

        Date now = new Date ();

        SimpleDateFormat dateFormat = new SimpleDateFormat (dateformat); // You can easily modify the date format

        String hehe = dateFormat.format (now);

        return hehe;

    }

      

    // Get the number of days between the current date and this Sunday

    private int getMondayPlus () {

        Calendar cd = Calendar.getInstance ();

        // Get today is the day of the week, Sunday is the first day, Tuesday is the second day ...

        int dayOfWeek = cd.get (Calendar.DAY_OF_WEEK) -1; // Because Chinese Monday is used as the first day, here is reduced by 1

        if (dayOfWeek == 1) {

            return 0;

        } else {

            return 1-dayOfWeek;

        }

    }

      

    // Get the date of this Monday

    public String getMondayOFWeek () {

         weeks = 0;

         int mondayPlus = this.getMondayPlus ();

         GregorianCalendar currentDate = new GregorianCalendar ();

         currentDate.add (GregorianCalendar.DATE, mondayPlus);

         Date monday = currentDate.getTime ();

           

         DateFormat df = DateFormat.getDateInstance ();

         String preMonday = df.format (monday);

         return preMonday;

    }

      

  // Get the date of Saturday of the corresponding week

    public String getSaturday () {

        int mondayPlus = this.getMondayPlus ();

        GregorianCalendar currentDate = new GregorianCalendar ();

        currentDate.add (GregorianCalendar.DATE, mondayPlus + 7 * weeks + 6);

        Date monday = currentDate.getTime ();

        DateFormat df = DateFormat.getDateInstance ();

        String preMonday = df.format (monday);

        return preMonday;

    }

      

 // get the date of last Sunday

    public String getPreviousWeekSunday () {

        weeks = 0;

        weeks--;

        int mondayPlus = this.getMondayPlus ();

        GregorianCalendar currentDate = new GregorianCalendar ();

        currentDate.add (GregorianCalendar.DATE, mondayPlus + weeks);

        Date monday = currentDate.getTime ();

        DateFormat df = DateFormat.getDateInstance ();

        String preMonday = df.format (monday);

        return preMonday;

    }

  

 // get the date of last Monday

    public String getPreviousWeekday () {

        weeks--;

        int mondayPlus = this.getMondayPlus ();

        GregorianCalendar currentDate = new GregorianCalendar ();

        currentDate.add (GregorianCalendar.DATE, mondayPlus + 7 * weeks);

        Date monday = currentDate.getTime ();

        DateFormat df = DateFormat.getDateInstance ();

        String preMonday = df.format (monday);

        return preMonday;

    }

      

    // get the date of next Monday

    public String getNextMonday () {

        weeks ++;

        int mondayPlus = this.getMondayPlus ();

        GregorianCalendar currentDate = new GregorianCalendar ();

        currentDate.add (GregorianCalendar.DATE, mondayPlus + 7);

        Date monday = currentDate.getTime ();

        DateFormat df = DateFormat.getDateInstance ();

        String preMonday = df.format (monday);

        return preMonday;

    }

      

 // get the date of next Sunday

    public String getNextSunday () {

          

        int mondayPlus = this.getMondayPlus ();

        GregorianCalendar currentDate = new GregorianCalendar ();

        currentDate.add (GregorianCalendar.DATE, mondayPlus + 7 + 6);

        Date monday = currentDate.getTime ();

        DateFormat df = DateFormat.getDateInstance ();

        String preMonday = df.format (monday);

        return preMonday;

    }

      

      

      

    private int getMonthPlus () {

        Calendar cd = Calendar.getInstance ();

        int monthOfNumber = cd.get (Calendar.DAY_OF_MONTH);

        cd.set (Calendar.DATE, 1); // Set the date to the first day of the month

        cd.roll (Calendar.DATE, -1); // The date rolls back one day, which is the last day

        MaxDate = cd.get (Calendar.DATE);

        if (monthOfNumber == 1) {

            return -MaxDate;

        } else {

            return 1-monthOfNumber;

        }

    }

      

  // Get the date of the last day of the previous month

    public String getPreviousMonthEnd () {

        String str = "";

       SimpleDateFormat sdf = new SimpleDateFormat ("yyyy-MM-dd");

  

       Calendar lastDate = Calendar.getInstance ();

      lastDate.add (Calendar.MONTH, -1); // minus one month

      lastDate.set (Calendar.DATE, 1); // Set the date to the first day of the month

      lastDate.roll (Calendar.DATE, -1); // The date rolls back one day, which is the last day of the month

       str = sdf.format (lastDate.getTime ());

       return str;

    }

      

  // Get the date of the first day of the next month

    public String getNextMonthFirst () {

        String str = "";

       SimpleDateFormat sdf = new SimpleDateFormat ("yyyy-MM-dd");

  

       Calendar lastDate = Calendar.getInstance ();

      lastDate.add (Calendar.MONTH, 1); // minus one month

      lastDate.set (Calendar.DATE, 1); // Set the date to the first day of the month

       str = sdf.format (lastDate.getTime ());

       return str;

    }

      

  // Get the date of the last day of the next month

    public String getNextMonthEnd () {

        String str = "";

       SimpleDateFormat sdf = new SimpleDateFormat ("yyyy-MM-dd");

  

       Calendar lastDate = Calendar.getInstance ();

      lastDate.add (Calendar.MONTH, 1); // Add one month

      lastDate.set (Calendar.DATE, 1); // Set the date to the first day of the month

      lastDate.roll (Calendar.DATE, -1); // The date rolls back one day, which is the last day of the month

       str = sdf.format (lastDate.getTime ());

       return str;

    }

      

    // Get the date of the last day of next year

    public String getNextYearEnd () {

        String str = "";

       SimpleDateFormat sdf = new SimpleDateFormat ("yyyy-MM-dd");

  

      Calendar lastDate = Calendar.getInstance ();

      lastDate.add (Calendar.YEAR, 1); // Add a year

      lastDate.set (Calendar.DAY_OF_YEAR, 1);

     lastDate.roll (Calendar.DAY_OF_YEAR, -1);

       str = sdf.format (lastDate.getTime ());

       return str;

    }

      

  // Get the date of the first day of next year

    public String getNextYearFirst () {

        String str = "";

       SimpleDateFormat sdf = new SimpleDateFormat ("yyyy-MM-dd");

  

      Calendar lastDate = Calendar.getInstance ();

      lastDate.add (Calendar.YEAR, 1); // Add a year

      lastDate.set (Calendar.DAY_OF_YEAR, 1);

           str = sdf.format (lastDate.getTime ());

      return str;

          

    }

      

  // Get how many days this year

    private int getMaxYear () {

        Calendar cd = Calendar.getInstance ();

        cd.set (Calendar.DAY_OF_YEAR, 1); // Set the date to the first day of the year

        cd.roll (Calendar.DAY_OF_YEAR, -1); // Roll the date back one day.

        int MaxYear = cd.get (Calendar.DAY_OF_YEAR);

        return MaxYear;

    }

      

    private int getYearPlus () {

        Calendar cd = Calendar.getInstance ();

        int yearOfNumber = cd.get (Calendar.DAY_OF_YEAR); // Get day is the day of the year

        cd.set (Calendar.DAY_OF_YEAR, 1); // Set the date to the first day of the year

        cd.roll (Calendar.DAY_OF_YEAR, -1); // Roll the date back one day.

        int MaxYear = cd.get (Calendar.DAY_OF_YEAR);

        if (yearOfNumber == 1) {

            return -MaxYear;

        } else {

            return 1-yearOfNumber;

        }

    }

  // Get the date of the first day of the year

    public String getCurrentYearFirst () {

        int yearPlus = this.getYearPlus ();

        GregorianCalendar currentDate = new GregorianCalendar ();

        currentDate.add (GregorianCalendar.DATE, yearPlus);

        Date yearDay = currentDate.getTime ();

        DateFormat df = DateFormat.getDateInstance ();

        String preYearDay = df.format (yearDay);

        return preYearDay;

    }

      

      

  // Get the date of the last day of the year *

    public String getCurrentYearEnd () {

Date date = new Date ();

        SimpleDateFormat dateFormat = new SimpleDateFormat ("yyyy"); // You can easily modify the date format

        String years = dateFormat.format (date);

        return years + "-12-31";

    }

      

      

  // Get the date of the first day of the previous year *

    public String getPreviousYearFirst () {

        Date date = new Date ();

        SimpleDateFormat dateFormat = new SimpleDateFormat ("yyyy"); // You can easily modify the date format

        String years = dateFormat.format (date); int years_value = Integer.parseInt (years);

        years_value--;

        return years_value + "-1-1";

    }

      

  // Get the date of the last day of the previous year

    public String getPreviousYearEnd () {

        weeks--;

        int yearPlus = this.getYearPlus ();

        GregorianCalendar currentDate = new GregorianCalendar ();

        currentDate.add (GregorianCalendar.DATE, yearPlus + MaxYear * weeks + (MaxYear-1));

        Date yearDay = currentDate.getTime ();

        DateFormat df = DateFormat.getDateInstance ();

        String preYearDay = df.format (yearDay);

        getThisSeasonTime (11);

        return preYearDay;

    }

      

  // Get this quarter

    public String getThisSeasonTime (int month) {

        int array [] [] = {{1,2,3}, {4,5,6}, {7,8,9}, {10,11,12}};

        int season = 1;

        if (month> = 1 && month <= 3) {

            season = 1;

        }

        if (month> = 4 && month <= 6) {

            season = 2;

        }

        if (month> = 7 && month <= 9) {

            season = 3;

        }

        if (month> = 10 && month <= 12) {

            season = 4;

        }

        int start_month = array [season-1] [0];

        int end_month = array [season-1] [2];

          

        Date date = new Date ();

        SimpleDateFormat dateFormat = new SimpleDateFormat ("yyyy"); // You can easily modify the date format

        String years = dateFormat.format (date);

        int years_value = Integer.parseInt (years);

          

        int start_days = 1; //years+"-"+String.valueOf(start_month)+"-1 "; // getLastDayOfMonth (years_value, start_month);

        int end_days = getLastDayOfMonth (years_value, end_month);

        String seasonDate = years_value + "-" + start_month + "-" + start_days + ";" + years_value + "-" + end_month + "-" + end_days;

        return seasonDate;

          

    }

      

    / **

     * Get the last day of a year and month

     * @param year

     * @param month month

     * @return last day

     * /

   private int getLastDayOfMonth (int year, int month) {

         if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8

                   || month == 10 || month == 12) {

               return 31;

         }

         if (month == 4 || month == 6 || month == 9 || month == 11) {

               return 30;

         }

         if (month == 2) {

               if (isLeapYear (year)) {

                   return 29;

               } else {

                   return 28;

               }

         }

         return 0;

   }

   / **

    * Whether it is a leap year

    * @param year

    * @return

    * /

  public boolean isLeapYear (int year) {

        return (year% 4 == 0 && year% 100! = 0) || (year% 400 == 0);

  }

}