输入年月日格式yyyyMMdd，判断是否是周末

 /**
	 * 判断是否是周末
	 * @param date 表示日期的字符串，比如20100424
	 * @param pattern 描述日期和时间格式的模式，比如yyyyMMdd
	 * @return
	 * @throws ParseException
	 */
    public boolean isWeekend(String date,String pattern) throws ParseException
    {
    	SimpleDateFormat df = new SimpleDateFormat(pattern);
	    Date time = df.parse(date);
	    Calendar cal = Calendar.getInstance();
	    cal.setTime(time);
		
	    int day = cal.get(Calendar.DAY_OF_WEEK);
	    
	    if (day == Calendar.SATURDAY || day == Calendar.SUNDAY)
	    {
	    	return true;
	    }
	    else
	    {
	    	return false;
	    }
    }