Java获取近两年和近六个月（存在bug）

	private List<String> getNearDate(String isYear){
		List<String> resultList = new ArrayList<String>();
		Calendar cal = Calendar.getInstance();
		if("0".equals(isYear)){
			//近六个月
			cal.set(Calendar.MONTH, cal.get(Calendar.MONTH)+1); //要先+1,才能把本月的算进去
			for(int i=0; i<6; i++){  
	            cal.set(Calendar.MONTH, cal.get(Calendar.MONTH)-1); //逐次往前推1个月  
	            resultList.add(String.valueOf(cal.get(Calendar.YEAR)) + (cal.get(Calendar.MONTH)+1 < 10 ? "0" + (cal.get(Calendar.MONTH)+1) : (cal.get(Calendar.MONTH)+1)));
	        }
		}else {
			//近两年
			int nowYear = cal.get(Calendar.YEAR);
			int lastYear = nowYear - 1 ;
			resultList.add(String.valueOf(nowYear)); 
			resultList.add(String.valueOf(lastYear)); 
		}
		
		return resultList;
	} 	private List<String> getNearDate(String isYear