code: public static String orderByDefault(Class<?> entityClass) {
          StringBuilder sql = new StringBuilder();
          String orderByClause = EntityHelper.getOrderByClause(entityClass);
          if (orderByClause.length() > 0) {
              sql.append(" ORDER BY ");
              sql.append(orderByClause);
          }
          return sql.toString();
      }
docs: 获取默认的orderBy，通过注解设置的
  
  @param entityClass
  @return