【SpringBoot】分页查询

1. Controller

    @ApiOperation("分页查询")
    @GetMapping("/page")
    public Result<PageResult> pageResultResult(EmployeePageQueryDTO employeePageQueryDTO) {
        System.out.println(employeePageQueryDTO.toString());
        PageResult pageResult = employeeService.pageQuery(employeePageQueryDTO);
        return Result.success(pageResult);
    }

2. Service

  这里使用PageHelper协助完成分页查询操作。PageHelper基于ThreadLocal实现，ThreadLocal会保存page和pageSize，在执行sql语句时候自动填补相应的limit语句。

    @Override
    public PageResult pageQuery(EmployeePageQueryDTO employeePageQueryDTO) {
        PageHelper.startPage(employeePageQueryDTO.getPage(), employeePageQueryDTO.getPageSize());
        Page<Employee> employeePage = employeeMapper.pageQuery(employeePageQueryDTO);
        val total = employeePage.getTotal();
        val result = employeePage.getResult();
        return new PageResult(total, result);
    }

3. Mapper

  这里使用 where 标签设置查询条件，使用 if 标签判断 name 字段是否为空。这里对于 name 字段使用模糊查询进行匹配，使用 concat 进行连接。

    <select id="pageQuery" resultType="com.sky.entity.Employee">
        select * from employee
        <where>
            <if test="name!=null and name!=''">
                and name like concat('%', #{name}, '%')
            </if>
        </where>
        order by create_time desc
    </select>