CalendarUtils

import java.util.Calendar;
import java.util.Date;

public class CalendarUtils {
	/**
	 * 得到本月的第一天
	 * 
	 * @return
	 */
	public static Date getMonthFirstDay() {
		Calendar calendar = Calendar.getInstance();
		calendar.set(Calendar.DAY_OF_MONTH, calendar
				.getActualMinimum(Calendar.DAY_OF_MONTH));

		return calendar.getTime();
	}

	public static Date getMonthFirstDay(Date date) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		calendar.set(Calendar.DAY_OF_MONTH, calendar
				.getActualMinimum(Calendar.DAY_OF_MONTH));

		return calendar.getTime();
	}

	/**
	 * 时间加减
	 * 
	 * @param currentDate
	 * @param delta
	 * @return
	 */
	public static Date addTime(Date currentDate, int delta) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(currentDate);
		calendar.add(Calendar.MINUTE, delta);

		return calendar.getTime();
	}

	/**
	 * 月份加减
	 * 
	 * @param currentDate
	 * @param delta
	 * @return
	 */
	public static Date addMonth(Date currentDate, int delta) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(currentDate);
		calendar.add(Calendar.MONTH, delta);

		return calendar.getTime();
	}

	/**
	 * 月份加减
	 * 
	 * @param currentDate
	 * @param delta
	 * @return
	 */
	public static Date addDay(Date currentDate, int delta) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(currentDate);
		calendar.add(Calendar.DATE, delta);

		return calendar.getTime();
	}

	/**
	 * 年份加减
	 * 
	 * @param currentDate
	 * @param delta
	 * @return
	 */
	public static Date addYear(Date currentDate, int delta) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(currentDate);
		calendar.add(Calendar.YEAR, delta);

		return calendar.getTime();
	}

	/**
	 * 得到本月的最后一天
	 * 
	 * @return
	 */
	public static Date getMonthLastDay() {
		Calendar calendar = Calendar.getInstance();
		calendar.set(Calendar.DAY_OF_MONTH, calendar
				.getActualMaximum(Calendar.DAY_OF_MONTH));
		return calendar.getTime();
	}

	public static Date getMonthLastDay(Date date) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		calendar.set(Calendar.DAY_OF_MONTH, calendar
				.getActualMaximum(Calendar.DAY_OF_MONTH));
		return calendar.getTime();
	}

	/**
	 * 
	 * @param year
	 *            int 年份
	 * @param month
	 *            int 月份
	 * 
	 * @return int 某年某月的最后一天
	 */
	public static int getLastDayOfMonth(int year, int month) {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.YEAR, year);
		cal.set(Calendar.MONTH, month);
		// 某年某月的最后一天
		return cal.getActualMaximum(Calendar.DATE);
	}

	/**
	 * 根据年份与月份得到Date
	 * 
	 * @param year
	 * @param month
	 * @return
	 */
	public static Date getDate(int year, int month) {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.YEAR, year);
		cal.set(Calendar.MONTH, month);
		cal.set(Calendar.DATE, 1);
		return cal.getTime();
	}

	/**
	 * 得到当年的第一天
	 * 
	 * @param year
	 * @return
	 */
	public static Date getYearFirstDay(int year) {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.YEAR, year);
		cal.set(Calendar.MONTH, 0);
		cal.set(Calendar.DATE, 1);
		return cal.getTime();
	}

	/**
	 * 得到当年的最后一天
	 * 
	 * @param year
	 * @return
	 */
	public static Date getYearLastDay(int year) {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.YEAR, year);
		cal.set(Calendar.MONTH, 11);
		cal.set(Calendar.DATE, 1);
		return cal.getTime();
	}
}