获得当前周的第一天和最后一天

/**
	 * 得到本周周一
	 * 
	 * @return yyyy-MM-dd
	 */
	public static String getMondayOfThisWeek() {
		Calendar c = Calendar.getInstance();
		int dayofweek = c.get(Calendar.DAY_OF_WEEK) - 1;
		if (dayofweek == 0)
			dayofweek = 7;
		c.add(Calendar.DATE, -dayofweek + 1);
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
		return sdf.format(c.getTime());
	}

	/**
	 * 得到本周周日
	 * 
	 * @return yyyy-MM-dd
	 */
	public static String getSundayOfThisWeek() {
		Calendar c = Calendar.getInstance();
		int dayofweek = c.get(Calendar.DAY_OF_WEEK) - 1;
		if (dayofweek == 0)
			dayofweek = 7;
		c.add(Calendar.DATE, -dayofweek + 7);
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
		return sdf.format(c.getTime());
	}

	/**
	 * 得到本月最后一天
	 * 
	 * @return
	 */
	public static String getLastDateOfMonth() {
		SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
		Calendar cal = Calendar.getInstance();
		cal.setTime(new Date());
		int days = cal.getActualMaximum(Calendar.DAY_OF_MONTH);
		cal.set(Calendar.DAY_OF_MONTH, days);
		String result = format.format(cal.getTime());
		System.out.println("一个月最后一天" + result);
		return result;
	}

	/**
	 * 得到本月第一天
	 * 
	 * @return
	 */
	public static String getFristDateOfMonth() {
		SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
		Calendar cal = Calendar.getInstance();
		cal.setTime(new Date());
		int days = cal.getActualMinimum(Calendar.DAY_OF_MONTH);
		cal.set(Calendar.DAY_OF_MONTH, days);
		String result = format.format(cal.getTime());
		System.out.println("一个月第一天" + result);
		return result;
	}