java获取某月，某季度的第一天和最后一天

/**
 * 某一个月第一天和最后一天
 * 
 * @param date 指定日期
 * @param pattern 日期格式
 * @param isNeedHms是否需要时分秒
 * @return
 */
public static Map getFirstLastDayByMonth(Date date,
		String pattern, boolean isNeedHms) {
	SimpleDateFormat df = new SimpleDateFormat(pattern);
	Calendar calendar = Calendar.getInstance();

	calendar.setTime(date);
	Date theDate = calendar.getTime();

	// 第一天
	GregorianCalendar gcLast = (GregorianCalendar) Calendar.getInstance();
	gcLast.setTime(theDate);
	gcLast.set(Calendar.DAY_OF_MONTH, 1);
	String day_first = df.format(gcLast.getTime());
	StringBuffer str = new StringBuffer().append(day_first);
	if (isNeedHms)
		str.append(" 00:00:00");
	day_first = str.toString();

	// 最后一天
	calendar.add(Calendar.MONTH, 1); // 加一个月
	calendar.set(Calendar.DATE, 1); // 设置为该月第一天
	calendar.add(Calendar.DATE, -1); // 再减一天即为上个月最后一天
	String day_last = df.format(calendar.getTime());
	StringBuffer endStr = new StringBuffer().append(day_last);
	if (isNeedHms)
		endStr.append(" 23:59:59");
	day_last = endStr.toString();

	Map map = new HashMap();
	map.put("first", day_first);
	map.put("last", day_last);
	return map;
}



/**
 * 获取当前季度
 *
 */
public static String getQuarter() {
	Calendar c = Calendar.getInstance();
	int month = c.get(c.MONTH) + 1;
	int quarter = 0;
	if (month >= 1 && month <= 3) {
		quarter = 1;
	} else if (month >= 4 && month <= 6) {
		quarter = 2;
	} else if (month >= 7 && month <= 9) {
		quarter = 3;
	} else {
		quarter = 4;
	}
	return quarter + "";
}

/**
 * 获取某季度的第一天和最后一天
 *	@param num第几季度
 */
public static String[] getCurrQuarter(int num) {
	String[] s = new String[2];
	String str = "";
	// 设置本年的季
	Calendar quarterCalendar = null;
	switch (num) {
		case 1: // 本年到现在经过了一个季度，在加上前4个季度
			quarterCalendar = Calendar.getInstance();
			quarterCalendar.set(Calendar.MONTH, 3);
			quarterCalendar.set(Calendar.DATE, 1);
			quarterCalendar.add(Calendar.DATE, -1);
			str = DateUtils.formatDate(quarterCalendar.getTime(), "yyyy-MM-dd");
			s[0] = str.substring(0, str.length() - 5) + "01-01";
			s[1] = str;
			break;
		case 2: // 本年到现在经过了二个季度，在加上前三个季度
			quarterCalendar = Calendar.getInstance();
			quarterCalendar.set(Calendar.MONTH, 6);
			quarterCalendar.set(Calendar.DATE, 1);
			quarterCalendar.add(Calendar.DATE, -1);
			str = DateUtils.formatDate(quarterCalendar.getTime(), "yyyy-MM-dd");
			s[0] = str.substring(0, str.length() - 5) + "04-01";
			s[1] = str;
			break;
		case 3:// 本年到现在经过了三个季度，在加上前二个季度
			quarterCalendar = Calendar.getInstance();
			quarterCalendar.set(Calendar.MONTH, 9);
			quarterCalendar.set(Calendar.DATE, 1);
			quarterCalendar.add(Calendar.DATE, -1);
			str = DateUtils.formatDate(quarterCalendar.getTime(), "yyyy-MM-dd");
			s[0] = str.substring(0, str.length() - 5) + "07-01";
			s[1] = str;
			break;
		case 4:// 本年到现在经过了四个季度，在加上前一个季度
			quarterCalendar = Calendar.getInstance();
			str = DateUtils.formatDate(quarterCalendar.getTime(), "yyyy-MM-dd");
			s[0] = str.substring(0, str.length() - 5) + "10-01";
			s[1] = str.substring(0, str.length() - 5) + "12-31";
			break;
	}
	return s;
}

/**
 * 用途：以指定的格式格式化日期字符串
 * @param pattern 字符串的格式
 * @param currentDate 被格式化日期
 * @return String 已格式化的日期字符串
 * @throws NullPointerException 如果参数为空
 */
public static String formatDate(Date currentDate, String pattern){
    if(currentDate == null || "".equals(pattern) || pattern == null){
    	return null;
    }
    SimpleDateFormat sdf = new SimpleDateFormat(pattern);
    return sdf.format(currentDate);
}