Mybatis-plus分页查询和条件查询通用写法

﹏ヽ暗。殇╰゛Y 2021-07-25 01:53 616阅读 0赞

# 一 查询条件VO #

/**
    * @className: TeacherQueryVo
    * @description: 讲师查询条件封装
    * @date: 2020/11/18
    * @author: cakin
    */
    @ApiModel("Teacher查询对象")
    @Data
    public class TeacherQueryVo implements Serializable {
        private static final long serialVersionUID = 1L;
    
        @ApiModelProperty(value = "讲师姓名")
        private String name;
    
        @ApiModelProperty(value = "讲师级别")
        private Integer level;
    
        @ApiModelProperty(value = "开始时间")
        private String joinDateBegin;
    
        @ApiModelProperty(value = "结束时间")
        private String joinDateEnd;
    }

# 二 讲师控制器中的分页和条件查询 #

/**
    * 功能描述：分页和条件查询
    *
    * @param page           当前页码
    * @param limit          每页记录数
    * @param teacherQueryVo 查询条件封装
    * @return R 返回给前端的数据
    * @author cakin
    * @date 2020/11/18
    */
    @ApiOperation("讲师分页列表")
    @GetMapping("list/{page}/{limit}")
    public R listPage(@ApiParam(value = "当前页码", required = true) @PathVariable Long page,
                      @ApiParam(value = "每页记录数", required = true) @PathVariable Long limit,
                      @ApiParam("讲师列表查询对象") TeacherQueryVo teacherQueryVo) {
        // 分页参数
        Page<Teacher> pageParam = new Page<>(page, limit);
        IPage<Teacher> pageModel = teacherService.selectPage(pageParam, teacherQueryVo);
        List<Teacher> records = pageModel.getRecords();
        long total = pageModel.getTotal();
        return R.ok().data("total", total).data("rows", records);
    }

# 三 讲师服务层实现 #

/**
    * @className: TeacherServiceImpl
    * @description: 讲师 服务实现类
    * @date: 2020/11/18
    * @author: cakin
    */
    @Service
    public class TeacherServiceImpl extends ServiceImpl<TeacherMapper, Teacher> implements TeacherService {
        /**
         * 功能描述：显示分页查询列表
         *
         * @author cakin
         * @date 2020/11/18
         * @param pageParam 分页查询参数
         * @param teacherQueryVo 条件查询参数
         * @return IPage<Teacher> 分页信息
         */
        @Override
        public IPage<Teacher> selectPage(Page<Teacher> pageParam, TeacherQueryVo teacherQueryVo) {
            // 1 排序：按照sort字段排序
            QueryWrapper<Teacher> queryWrapper = new QueryWrapper<>();
            queryWrapper.orderByAsc("sort");
            // 2 有分页查询 无条件查询
            if (teacherQueryVo == null) {
                return baseMapper.selectPage(pageParam, queryWrapper);
            }
            // 3 构造条件查询
            String name = teacherQueryVo.getName();
            Integer level = teacherQueryVo.getLevel();
            String joinDateBegin = teacherQueryVo.getJoinDateBegin();
            String joinDateEnd = teacherQueryVo.getJoinDateEnd();
            if (!StringUtils.isEmpty(name)) {
                queryWrapper.likeRight("name", name);
            }
            if (level != null) {
                queryWrapper.eq("level", level);
            }
            if (!StringUtils.isEmpty(joinDateBegin)) {
                queryWrapper.ge("join_date", joinDateBegin);
            }
            if (!StringUtils.isEmpty(joinDateEnd)) {
                queryWrapper.le("join_date", joinDateEnd);
            }
            // 2 有分页查询 有条件查询
            return baseMapper.selectPage(pageParam, queryWrapper);
        }

# 四 Swagger测试 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70][]

查询结果

{
        "success": true,
        "code": 20000,
        "message": "成功",
        "data": {
            "total": 2,
            "rows": [{
                    "id": "2",
                    "gmtCreate": "2018-03-30 18:28:26",
                    "gmtModified": "2020-04-14 17:40:36",
                    "name": "周润发",
                    "intro": "中国人民大学附属中学数学一级教师",
                    "career": "中国科学院数学与系统科学研究院应用数学专业博士，研究方向为数字图像处理，中国工业与应用数学学会会员。参与全国教育科学“十五”规划重点课题“信息化进程中的教育技术发展研究”的子课题“基与课程改革的资源开发与应用”，以及全国“十五”科研规划全国重点项目“掌上型信息技术产品在教学中的运用和开发研究”的子课题“用技术学数学”。",
                    "level": 2,
                    "avatar": "https://guli-file-helen.oss-cn-beijing.aliyuncs.com/avatar/2020/04/14/f606ed5b-1d46-43a1-945c-3e1b3b58fc0a.jpg",
                    "sort": 1,
                    "joinDate": "2019-10-28",
                    "deleted": false
                },
                {
                    "id": "4",
                    "gmtCreate": "2018-04-03 14:13:51",
                    "gmtModified": "2019-10-29 19:52:46",
                    "name": "周杰伦",
                    "intro": "长期从事考研政治课讲授和考研命题趋势与应试对策研究。考研辅导新锐派的代表。",
                    "career": "政治学博士、管理学博士后，北京师范大学马克思主义学院副教授。多年来总结出了一套行之有效的应试技巧与答题方法，针对性和实用性极强，能帮助考生在轻松中应考，在激励的竞争中取得高分，脱颖而出。",
                    "level": 1,
                    "avatar": "https://online-teach-file-helen.oss-cn-beijing.aliyuncs.com/avatar/2019/11/25/fee1e99f-8852-4da0-a256-9732e55bb608.jpg",
                    "sort": 1,
                    "joinDate": "2019-10-27",
                    "deleted": false
                }
            ]
        }
    }

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