通用Mapper进行分页查询

末蓝、 2023-07-03 04:50 17阅读 0赞

# 通用Mapper进行分页查询 #

什么也不说，直接上代码解释。

## 1.1引入分页助手依赖和通用Mapper依赖 ##

<dependency>
    			
                <groupId>tk.mybatis</groupId>
                <artifactId>mapper-spring-boot-starter</artifactId>
                <version>2.1.5</version>
            </dependency>
    		<!--分页助手依赖->
            <dependency>
                <groupId>com.github.pagehelper</groupId>
                <artifactId>pagehelper-spring-boot-starter</artifactId>
                <version>1.2.12</version>
            </dependency>

## 1.2DAO层 ##

注意：不能导错依赖 import tk.mybatis.mapper.common.Mapper

import com.mayday.auth.pojo.User;
    import org.apache.ibatis.annotations.Delete;
    import org.apache.ibatis.annotations.Insert;
    import org.apache.ibatis.annotations.Param;
    import tk.mybatis.mapper.common.Mapper;
    
    public interface UserMapper extends Mapper<User> {
    }

## 1.3Service层 ##

/**
         * 分页查询
         *
         * @param key    关键字查询
         * @param page   页数
         * @param size   每页数量
         * @param desc   排序方式
         * @param sortBy 需要排序的字段
         * @param status 用户状态
         * @return
         */
        public PageResult<User> queryUserByPage(String key, int page, int size, Boolean desc, String sortBy, Boolean status) {
            //分页
            PageHelper.startPage(page, size);
            //过滤
            Example example = new Example(User.class);
            if (status != null) {
                example.setDistinct(status);
            }
            if (StringUtils.isNotBlank(key)) {
                //过滤条件
                example.createCriteria().orLike("username", "%" + key.toLowerCase() + "%").orEqualTo("phone",key.toLowerCase());
            }
            //根据相应的字段进行排序
            if (StringUtils.isNotBlank(sortBy)) {
                String orderByClause = sortBy + (desc ? " DESC" : " ASC");
                example.setOrderByClause(orderByClause);
            }
            //查询
            List<User> users = userMapper.selectByExample(example);
            if (CollectionUtils.isEmpty(users)) {
                return null;
            }
            users.stream().forEach(user -> user.setPassword(null));
            //解析分页结果
            PageInfo<User> info = new PageInfo<>(users);
            return new PageResult<>(info.getTotal(), users);
    
        }

## 1.4Controller层 ##

/**
         * 分页查询
         * @param key
         * @param page
         * @param size
         * @param desc
         * @param sortBy
         * @param status
         * @return
         */
        @GetMapping("/userList")
        public Result queryUserByPage(@RequestParam(value = "key", required = false) String key,
                                      @RequestParam(value = "page", defaultValue = "1") Integer page,
                                      @RequestParam(value = "rows", defaultValue = "5") Integer size,
                                      @RequestParam(value = "desc", defaultValue = "false") Boolean desc,
                                      @RequestParam(value = "sortBy", required = false) String sortBy,
                                      @RequestParam(value = "status", required = false) Boolean status) {
            PageResult<User> pageResult = userService.queryUserByPage(key, page, size, desc, sortBy, status);
            if (pageResult == null) {
                return new Result(false, StatusCode.QUERY_FAIL);
            }
            return new Result(true, StatusCode.OK, pageResult);
        }