学习Java的Date、Calendar日期操作

学习Java的Date、Calendar日期操作

本文介绍了java开发过程中日期相关操作，分享的代码如下：

package jse;

import java.io.UnsupportedEncodingException;

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.util.Calendar;

import java.util.Date;

import java.util.Locale;

/**

* 常用日期操作

*

* @author puck

* createDate 2015-07-30 22:54:38

*/

public class TestDate

{

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

{

Calendar cal = Calendar.getInstance();

// cal.add(Calendar.DAY_OF_MONTH, -48);

System.out.println(dateToString(cal));

}

/**

* 日期格式化

* @param date

* @return

*/

public static String dateToString(Date date)

{

// SimpleDateFormat format = new SimpleDateFormat("y年MM月dd日 E HH时mm分ss秒", Locale.CHINA);

// SimpleDateFormat format = new SimpleDateFormat("y年M月d日 E H时m分s秒", Locale.CHINA);

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.CHINA); // example

return sdf.format(date);

}

/**

* 日期格式化

* @param date

* @return

*/

public static String dateToString(Calendar cal)

{

return dateToString(cal.getTime());

}

/**

* dateString 转 Calendar

*

* @param Date

* format:2015-06-16 date

* @return Calendar

* @throws ParseException

*/

public static Calendar dateStringToCalendar(String dateStr) throws ParseException

{

// Calendar cal = Calendar.getInstance();

// cal.clear();

// cal.set(Integer.parseInt(date.substring(0, 4)), Integer.parseInt(date.substring(5, 7)) - 1,

// Integer.parseInt(date.substring(8, 10)));

// return cal;

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

Date date = sdf.parse(dateStr);

Calendar cal = Calendar.getInstance();

cal.setTime(date);

return cal;

}

/**

* dateString 转 Date

*

* @param Date

* format:yyyy-MM-dd HH:mm:ss date

* @return Calendar

* @throws ParseException

*/

public static Date dateStringToDate(String date) throws ParseException

{

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

return sdf.parse(date);

}

/**

* Date Convert to Calendar

*

* @param date

* @return

*/

public static Calendar dateToCalendar(Date date)

{

Calendar c1 = Calendar.getInstance();

c1.setTime(date);

return c1;

}

/**

* Calendar Convert To Date

* @param cal

* @return

*/

public static Date CalendarToDate(Calendar cal)

{

return cal.getTime();

}

/**

* 计算两个日期相差年月日

*

* @param Date

* c1

* @param Date

* c2

* @return int[]{year, month, day}

*/

public int[] calculateDifferDay(Date d1, Date d2)

{

Calendar c1 = Calendar.getInstance();

c1.setTime(d1);

Calendar c2 = Calendar.getInstance();

c1.setTime(d2);

return calculateDifferDay(c1, c2);

}

/**

* 计算两个日期相差年月日

*

* @param Calendar

* c1

* @param Calendar

* c2

* @return int[]{year, month, day}

*/

public int[]VgIznUkqzc calculateDifferDay(Calendar c1, Calendar c2)

{

int[] p1 = { c1.get(Calendar.YEAR), c1.get(Calendar.MONTH), c1.get(Calendar.DAY_OF_MONTH) };

int[] p2 = { c2.get(Calendar.YEAR), c2.get(Calendar.MONTH), c2.get(Calendar.DAY_OF_MONTH) };

System.out.println("p1[0]=" + p1[0] + " p1[1]=" + p1[1] + " p1[2]=" + p1[2]);

System.out.println("p2[0]=" + p2[0] + " p2[1]=" + p2[1] + " p2[2]=" + p2[2]);

int year = p2[0] - p1[0];

int month = (p2[0] * 12) + p2[1] - ((p1[0] * 12) + p1[1]);

int day = (int) ((c2.getTimeInMillis() - c1.getTimeInMillis()) / (24 * 60 * 60 * 1000));

return new int[] { year, month, day };

}

/**

* 获取日期所在周的第一天

*

* @param c

* @return

*/

public static Calendar getLastDayOfWeek(Calendar c)

{

// SimpleDateFormat format2 = new SimpleDateFormat("y年M月d日 E H时m分s秒", Locale.CHINA);

// System.out.println("当前时间:" + format2.format(c.getTime()));

c.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);

// System.out.println("周一时间:" + format2.format(c.getTime()));

return c;

}

/**

* 日期加减

* @param c

* @param day

* @return

*/

public static Calendar addOrDecreaseDay(Calendar c, int day)

{

c.add(Calendar.DAY_OF_MONTH, day);

return c;

}

/**

* 获取月最后一天

* @param year

* @param month

* @return

*/

public static int getLastDayOfMonth(int year, int month)

{

Calendar c = Calendar.getInstance();

c.set(year, month - 1, 1);

return c.getActualMaximum(Calendar.DAY_OF_MONTH);

}

/**

* 获取月最后一天

* @param cal

* @return

*/

public static int getLastDayOfMonth(Calendar cal)

{

return cal.getActualMaximum(Calendar.DAY_OF_MONTH);

}

}

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