产生19位数字

/**
	 * 获得UniqId  19位
	 * 
	 */
	public long getUniqID(Long userId) {
		StringBuffer sb = new StringBuffer();
		long t = timer.getCurrentTime();
		sb.append(t);
		//产生19位的数字
		generate19WeiNumber(sb, userId);
		return Long.valueOf(sb.toString());
	}
	
	public static  void generate19WeiNumber(StringBuffer sb, Long userId){
		if(userId == null){
			userId = 0L;
		}
		int len = sb.length();
		int suffixLen = 19 - len;
		String userIdStr = String.valueOf(userId);
		if(userIdStr.length() >= suffixLen){
			sb.append(userIdStr.substring(0, suffixLen));
		}else{
			int temp = suffixLen - userIdStr.length();
			for(int i=0;i<temp;i++){
				sb.append("0");
			}
			sb.append(userIdStr);
		}
	}