code: public void init(Properties props) {
          if (dao != null) {
              throw new IllegalArgumentException("DaoUp is inited!!");
          }
          if (props.size() == 0) {
              throw new IllegalArgumentException("DaoUp props size=0!!!");
          }
          DataSource ds = buildDataSource(props);
          setDataSource(ds);
      }
docs: 给定一个Properties配置,不能为null!!!! 最起码要包含一个叫url的参数!!!
  @param props 配置信息