MyBatis-Puls 统一封装前端传递的分页、排序

封装方式是使用mybatis-Plus 中 mapper层传入page类自动完成分页操作的基础上，我们封装一个统一的page类，每次查询只需要前端传入 当前页、分页大小、
排序字段(多个逗号隔开)、排序方式(多个逗号隔开，与排序字段对应)
操作:
1、在controller层接收page参数
2、在传入mapper层时完成page类的完整构建,包括pageNum、pageSize、排序

样例
page工具类

/**
 * 分页查询实体类
 *
 */

@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"}); //替换其中的 "ascending", "descending" 为 "asc", "desc"

        String[] orderByArr = orderBy.split(StringUtils.SEPARATOR); // StringUtils.SEPARATOR =  ","
        String[] isAscArr = isAsc.split(StringUtils.SEPARATOR);
        //前面已经非空判断了 orderByArr isAscArr 长度一定大于0
        //isAscArr.length != 1 单个排序方式直接放行
        //isAscArr.length != 1 && isAscArr.length != orderByArr.length 单字段单排序保证 字段与排序数量要对应
        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;
    }

}

controller层

    /**
     * 查询测试单表列表
     */
    @SaCheckPermission("demo:demo:list")
    @GetMapping("/list")
    public TableDataInfo<TestDemoVo> list(TestDemoBo bo, PageQuery pageQuery) {
        return iTestDemoService.queryPageList(bo, pageQuery);
    }

serviceImpl 实现

    /**
     * 自定义分页查询
     */
    @Override
    public TableDataInfo<TestDemoVo> customPageList(TestDemoBo bo, PageQuery pageQuery) {
        LambdaQueryWrapper<TestDemo> lqw = buildQueryWrapper(bo);
        Page<TestDemoVo> result = baseMapper.customPageList(pageQuery.build(), lqw);
        return TableDataInfo.build(result);
    }

    private LambdaQueryWrapper<TestDemo> buildQueryWrapper(TestDemoBo bo) {
        Map<String, Object> params = bo.getParams();
        LambdaQueryWrapper<TestDemo> lqw = Wrappers.lambdaQuery();
        lqw.like(StringUtils.isNotBlank(bo.getTestKey()), TestDemo::getTestKey, bo.getTestKey());
        lqw.eq(StringUtils.isNotBlank(bo.getValue()), TestDemo::getValue, bo.getValue());
        lqw.between(params.get("beginCreateTime") != null && params.get("endCreateTime") != null,
            TestDemo::getCreateTime, params.get("beginCreateTime"), params.get("endCreateTime"));
        return lqw;
    }

mapper层

    Page<TestDemoVo> customPageList(@Param("page") Page<TestDemo> page, @Param("ew") Wrapper<TestDemo> wrapper);

xml

    <select id="customPageList" resultType="com.ruoyi.demo.domain.vo.TestDemoVo">
        SELECT * FROM test_demo ${ew.customSqlSegment}
    </select>