要实现一个功能，前端有这个箭头按钮，按一下就发后台进行排序

java的分页对象（若依自带无须改动）

@Data
public class PageQuery implements Serializable {

    private static final long serialVersionUID = 1L;

    /**
     * 分页大小
     */
    private Integer pageSize;

    /**
     * 当前页数
     */
    private Integer pageNum;

    /**
     * 排序列
     */
    private String orderByColumn;

    /**
     * 排序的方向desc或者asc
     */
    private String isAsc;

    /**
     * 当前记录起始索引 默认值
     */
    public static final int DEFAULT_PAGE_NUM = 1;

    /**
     * 每页显示记录数 默认值 默认查全部
     */
    public static final int DEFAULT_PAGE_SIZE = Integer.MAX_VALUE;

    public <T> Page<T> build() {
        Integer pageNum = ObjectUtil.defaultIfNull(getPageNum(), DEFAULT_PAGE_NUM);
        Integer pageSize = ObjectUtil.defaultIfNull(getPageSize(), DEFAULT_PAGE_SIZE);
        if (pageNum <= 0) {
            pageNum = DEFAULT_PAGE_NUM;
        }
        Page<T> page = new Page<>(pageNum, pageSize);
        List<OrderItem> orderItems = buildOrderItem();
        if (CollUtil.isNotEmpty(orderItems)) {
            page.addOrder(orderItems);
        }
        return page;
    }

    /**
     * 构建排序
     *
     * 支持的用法如下:
     * {isAsc:"asc",orderByColumn:"id"} order by id asc
     * {isAsc:"asc",orderByColumn:"id,createTime"} order by id asc,create_time asc
     * {isAsc:"desc",orderByColumn:"id,createTime"} order by id desc,create_time desc
     * {isAsc:"asc,desc",orderByColumn:"id,createTime"} order by id asc,create_time desc
     */
    private List<OrderItem> buildOrderItem() {
        if (StringUtils.isBlank(orderByColumn) || StringUtils.isBlank(isAsc)) {
            return null;
        }
        String orderBy = SqlUtil.escapeOrderBySql(orderByColumn);
        orderBy = StringUtils.toUnderScoreCase(orderBy);

        // 兼容前端排序类型
        isAsc = StringUtils.replaceEach(isAsc, new String[]{"ascending", "descending"}, new String[]{"asc", "desc"});

        String[] orderByArr = orderBy.split(",");
        String[] isAscArr = isAsc.split(",");
        if (isAscArr.length != 1 && isAscArr.length != orderByArr.length) {
            throw new ServiceException("排序参数有误");
        }

        List<OrderItem> list = new ArrayList<>();
        // 每个字段各自排序
        for (int i = 0; i < orderByArr.length; i++) {
            String orderByStr = orderByArr[i];
            String isAscStr = isAscArr.length == 1 ? isAscArr[0] : isAscArr[i];
            if ("asc".equals(isAscStr)) {
                list.add(OrderItem.asc(orderByStr));
            } else if ("desc".equals(isAscStr)) {
                list.add(OrderItem.desc(orderByStr));
            } else {
                throw new ServiceException("排序参数有误");
            }
        }
        return list;
    }

}

前端代码

<el-table v-if="showTable"  @header-click="handleHeaderCLick" 
		:header-cell-class-name="handleHeaderClass">
	<el-table-column label="教师超编(人)" prop="createTime" 	sortable="custom">
	....

js代码

// 需要设置这个，否则重置的时候箭头不会清空点亮
const showTable = ref(false);

// 默认排序
const defaultSort = ref({prop: 'createTime', order: 'ascending'});
/** 重置按钮操作 */
function resetQuery() {
  
  proxy.resetForm("queryRef");
  queryParams.value.orderByColumn = defaultSort.value.prop;
  queryParams.value.isAsc = defaultSort.value.order;
  // 重新刷一遍表单，清空箭头点亮
  // 在getList发后端接口时重新设为true
  showTable.value = false;
  handleQuery();
}


// 绑定箭头的，没有这个多个排序字段只会有一个亮
// 设置列的排序为我们自定义的排序
function handleHeaderClass({column}) {
  column.order = column.multiOrder
}	
// 点击表头进行排序
function handleHeaderCLick(column) {

	// 如果table不是@header-click而是@sort-change
	// 则为column.column.sortable。。。其余属性以此类推
  if (column.sortable !== 'custom') {
    return
  }
  switch (column.multiOrder) {
    case 'descending':
      column.multiOrder = 'ascending';
      break;
    case 'ascending':
      column.multiOrder = '';
      break;
    default:
      column.multiOrder = 'descending';
      break;
  }
  handleOrderChange(column.property, column.multiOrder)
}
function handleOrderChange(prop, order) {
  let orderByArr = queryParams.value.orderByColumn ? queryParams.value.orderByColumn.split(",") : [];
  let isAscArr = queryParams.value.isAsc ? queryParams.value.isAsc.split(",") : [];
  let propIndex = orderByArr.indexOf(prop)
  if (propIndex !== -1) {
    if (order) {
      //排序里已存在 只修改排序
      isAscArr[propIndex] = order;
    } else {
      //如果order为null 则删除排序字段和属性
      isAscArr.splice(propIndex, 1);//删除排序
      orderByArr.splice(propIndex, 1);//删除属性
    }
  } else {
    //排序里不存在则新增排序
    orderByArr.push(prop);
    isAscArr.push(order);
  }
  
  // queryParams是查询参数对象
  // 查询参数要有的排序字段
  //	合并排序
  queryParams.value.orderByColumn = orderByArr.join(",");
  queryParams.value.isAsc = isAscArr.join(",");
  // 获取列表方法，此时发后端接口
  getList();
}