常用工具類規整-DateUtil

package com.live.test.api.core.date.ju;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

/**
 * 日期工具類 基於 java.util.Calendar
 * 
 * @author live
 * @2020年2月19日 @下午
 */
public class DateUtil {

	/**
	 * yyyy_MM_dd
	 */
	public static final String FORMAT_yyyy_MM_dd = "yyyy-MM-dd";

	/**
	 * yyyy-MM
	 */
	public static final String FORMAT_yyyy_MM = "yyyy-MM";

	/**
	 * 1秒 的毫秒數
	 */
	public static final long MILLISECOND_OF_SECOND = 1000;
	/**
	 * 1分鐘 的毫秒數
	 */
	public static final long MILLISECOND_OF_MINUTE = MILLISECOND_OF_SECOND * 60;
	/**
	 * 1小時 的毫秒數
	 */
	public static final long MILLISECOND_OF_HOUR = MILLISECOND_OF_MINUTE * 60;
	/**
	 * 1天 的毫秒數
	 */
	public static final long MILLISECOND_OF_DAY = MILLISECOND_OF_HOUR * 24;

	/**
	 * 獲取當前時刻 的時間戳
	 * 
	 * @return 毫秒
	 */
	public static long getNowMillis() {
		return System.currentTimeMillis();
	}

	/**
	 * 獲取當前時刻 距離 次日0點0分0秒 的毫秒數
	 * 
	 * @return 毫秒
	 */
	public static long getNowToZeroMillis() {
		return getZeroMillis() - getNowMillis();
	}

	/**
	 * 獲取 次日0點0分0秒 的時間戳
	 * 
	 * @return 毫秒
	 */
	public static long getZeroMillis() {
		Calendar calendar = Calendar.getInstance();
		calendar.add(Calendar.DAY_OF_MONTH, 1);// 加1表示明天的0點
		calendar.set(Calendar.HOUR_OF_DAY, 0);// 24小時制
		calendar.set(Calendar.MINUTE, 0);
		calendar.set(Calendar.SECOND, 0);
		calendar.set(Calendar.MILLISECOND, 0);

		return calendar.getTimeInMillis();
	}

	/**
	 * 
	 */
	public static String format = "yyyy-MM-dd HH:mm:ss";

	/**
	 * 判斷兩個日期是否同日
	 * 
	 * @param date1
	 * @param date2
	 * @return
	 */
	public static boolean isEqualDay(Date date1, Date date2) {
		Calendar calendar1 = Calendar.getInstance();
		calendar1.setTime(date1);
		Calendar calendar2 = Calendar.getInstance();
		calendar2.setTime(date2);
		int i = calendar1.get(Calendar.DAY_OF_YEAR);
		int i2 = calendar2.get(Calendar.DAY_OF_YEAR);
		return i == i2;
	}

	/**
	 * 判斷兩個日期是否同周
	 * 
	 * @param date1
	 * @param date2
	 * @return
	 */
	public static boolean isEqualWeek(Date date1, Date date2) {
		Calendar calendar1 = Calendar.getInstance();
		calendar1.setTime(date1);
		Calendar calendar2 = Calendar.getInstance();
		calendar2.setTime(date2);
		int week1 = calendar1.get(Calendar.WEEK_OF_MONTH);
		int week2 = calendar2.get(Calendar.WEEK_OF_MONTH);
		return isEqualMonth(date1, date2) && week1 == week2;
	}

	/**
	 * 判斷兩個日期是否同月
	 * 
	 * @param date1
	 * @param date2
	 * @return
	 */
	public static boolean isEqualMonth(Date date1, Date date2) {
		Calendar calendar1 = Calendar.getInstance();
		calendar1.setTime(date1);

		Calendar calendar2 = Calendar.getInstance();
		calendar2.setTime(date2);
		return calendar1.get(Calendar.YEAR) == calendar2.get(Calendar.YEAR)
				&& calendar1.get(Calendar.MONTH) == calendar2.get(Calendar.MONTH);
	}

	/**
	 * 獲取指定年月的第一天
	 * 
	 * @param year
	 * @param month
	 * @return
	 */
	public static String getFirstDayOfMonth(int year, int month) {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.YEAR, year);
		cal.set(Calendar.MONTH, month - 1);
		int firstDay = cal.getMinimum(Calendar.DATE);
		cal.set(Calendar.DAY_OF_MONTH, firstDay);
		SimpleDateFormat sdf = new SimpleDateFormat(format);
		return sdf.format(cal.getTime());
	}

	/**
	 * 獲取指定年月的最後一天
	 * 
	 * @param year
	 * @param month
	 * @return
	 */
	public static String getLastDayOfMonth(int year, int month) {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.YEAR, year);
		cal.set(Calendar.MONTH, month - 1);
		int lastDay = cal.getActualMaximum(Calendar.DATE);
		cal.set(Calendar.DAY_OF_MONTH, lastDay);
		SimpleDateFormat sdf = new SimpleDateFormat(format);
		return sdf.format(cal.getTime());
	}

	public static String coverToString(Date date, String format) {
		return new SimpleDateFormat(format).format(date);
	}

	/**
	 * Date對象轉爲: 年月日
	 * 
	 * @param date
	 * @return
	 */
	public static String coverToDay(Date date) {
		return coverToString(date, FORMAT_yyyy_MM_dd);
	}

	/**
	 * Date對象轉爲: 年月
	 * 
	 * @param date
	 * @return
	 */
	public static String coverToMonth(Date date) {
		return coverToString(date, FORMAT_yyyy_MM);
	}
}

代碼地址：

github：https://github.com/sunxiaoning90/com_live_test/tree/master/com_live_test_javase/com_live_test_javase_core