code: private static String parseFieldsSql(String tableName, Supplier<ConditionEnum>[] conditions) {
          final String[] sql = {"SELECT * FROM " + tableName};
          if (null == conditions) {
              return sql[0];
          }
          Stream.of(conditions)
                  .filter(conditionEnumSupplier -> conditionEnumSupplier.get().equals(ConditionEnum.FIELDS))
                  .findFirst()
                  .ifPresent(conditionEnumSupplier -> {
                      Fields      fields    = (Fields) conditionEnumSupplier;
                      Set<String> fieldsSet = fields.getFields();
                      sql[0] = "SELECT " + fieldsSet.stream().collect(Collectors.joining(",")) + " FROM " + tableName;
                  });
          return sql[0];
      }
docs: 解析Model字段
  
  @param tableName  表名
  @param conditions 条件
  @return 返回sql语句