package com.yong.util;
import java.util.Calendar;
import java.util.Date;

public class TestDate {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		System.out.println("当前时间："+ new Date().toLocaleString());
		System.out.println("当天0点时间："+ getTimesmorning().toLocaleString());
		System.out.println("当天24点时间："+ getTimesnight().toLocaleString());
		System.out.println("本周周一0点时间："+ getTimesWeekmorning().toLocaleString());
		System.out.println("本周周日24点时间："+ getTimesWeeknight().toLocaleString());
		System.out.println("本月初0点时间："+ getTimesMonthmorning().toLocaleString());
		System.out.println("本月未24点时间："+ getTimesMonthnight().toLocaleString());
	}

	// 获得当天0点时间
	public static Date getTimesmorning() {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.HOUR_OF_DAY, 0);
		cal.set(Calendar.SECOND, 0);
		cal.set(Calendar.MINUTE, 0);
		cal.set(Calendar.MILLISECOND, 0);
		return cal.getTime();
	}

	// 获得当天24点时间
	public static Date getTimesnight() {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.HOUR_OF_DAY, 24);
		cal.set(Calendar.SECOND, 0);
		cal.set(Calendar.MINUTE, 0);
		cal.set(Calendar.MILLISECOND, 0);
		return  cal.getTime();
	}

	// 获得本周一0点时间
	public static Date getTimesWeekmorning() {
		Calendar cal = Calendar.getInstance();
		cal.set(cal.get(Calendar.YEAR), cal.get(Calendar.MONDAY), cal.get(Calendar.DAY_OF_MONTH), 0, 0, 0);
		cal.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
		return  cal.getTime();
	}

	// 获得本周日24点时间
	public  static Date getTimesWeeknight() {
		Calendar cal = Calendar.getInstance();
		cal.setTime(getTimesWeekmorning());
		cal.add(Calendar.DAY_OF_WEEK, 7);
		return cal.getTime();
	}

	// 获得本月第一天0点时间
	public static Date getTimesMonthmorning() {
		Calendar cal = Calendar.getInstance();
		cal.set(cal.get(Calendar.YEAR), cal.get(Calendar.MONDAY), cal.get(Calendar.DAY_OF_MONTH), 0, 0, 0);
		cal.set(Calendar.DAY_OF_MONTH, cal.getActualMinimum(Calendar.DAY_OF_MONTH));
		return  cal.getTime();
	}

	// 获得本月最后一天24点时间
	public static Date getTimesMonthnight() {
		Calendar cal = Calendar.getInstance();
		cal.set(cal.get(Calendar.YEAR), cal.get(Calendar.MONDAY), cal.get(Calendar.DAY_OF_MONTH), 0, 0, 0);
		cal.set(Calendar.DAY_OF_MONTH, cal.getActualMaximum(Calendar.DAY_OF_MONTH));
		cal.set(Calendar.HOUR_OF_DAY, 24);
		return cal.getTime();
	}

}

2.结果

当前时间：2014-10-17 15:23:26
当天0点时间：2014-10-17 0:00:00
当天24点时间：2014-10-18 0:00:00
本周周一0点时间：2014-10-13 0:00:00
本周周日24点时间：2014-10-20 0:00:00
本月初0点时间：2014-10-1 0:00:00
本月未24点时间：2014-11-1 0:00:00