docs: protected void parseLimitValue() {
  		Matcher m = LIMIT_PATTERN.matcher(sql);
  		if (!m.find()) {
  			return;
  		}
  		int index = m.start();
  		String limitSql = sql.substring(index);
  		// System.out.println("limitSql:" + limitSql);
  		int count = StringUtils.countOccurrencesOf(limitSql, "?");
  
  		int paramCount = param.size();
  		if (count == 1) {
  			this.size = param.getInt(paramCount - 1);
  		}
  		else if (count == 2) {
  			this.start = param.getInt(paramCount - 2);
  			this.size = param.getInt(paramCount - 1);
  		}
  		else {
  			throw new IllegalArgumentException("怎么limit参数是" + count + "个?");
  		}
  	}