72 课程列表后端

建立实体类。

@Data
public class OneSubject {
    private String id;
    private String title;

    private List<String> children = new ArrayList<>();
}

@Data
public class TwoSubject {
    private String id;
    private String title;
}

controller。

    public R getAllSubject() {
        // 一级分类中已经包含了二级分类
        List<OneSubject> list = eduSubjectService.getAllSubject();
        return R.ok();
    }

serviceImpl。

  @Override
    public List<OneSubject> getAllSubject() {
        // 1.查询一级分类
       QueryWrapper<EduSubject> wrapperOne = new QueryWrapper<>();
       wrapperOne.eq("parentid", "0");
       List<EduSubject> firstList = baseMapper.selectList(wrapperOne);
        // 2.查询二级分类
        QueryWrapper<EduSubject> wrapperTwo = new QueryWrapper<>();
        wrapperTwo.eq("parentid", "0");
        List<EduSubject> secondList = baseMapper.selectList(wrapperOne);

        List<OneSubject> finalSubject = new ArrayList();
        // 3.封装一级分类


        // 4.封装二级分类

        return null;
    }