code: public DatabaseMetaData filterDataBaseMetaData(JdbcTemplate jdbcTemplate, Connection con,
                                                     DatabaseMetaData databaseMetaData) throws Exception {
          return databaseMetaData;
      }
docs: 对 databaseMetaData 做一些过滤,返回 {@linkplain DatabaseMetaData}，不能为 null
  
  @param databaseMetaData
  @return