@Data
public class OneSubject {
private String id;
private String title;
private List<TwoSubject> children = new ArrayList<>();
}


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.

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


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.

@GetMapping("getAllSubject")
public R getAllSubject(){
List<OneSubject> list = subjectService.getAllOneTwoSubject();
return R.Ok().data("list",list);
}


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.

//课程分类列表（树形）
@Override
public List<OneSubject> getAllOneTwoSubject() {
//1 查询所有一级分类
QueryWrapper<EduSubject> wrapperOne = new QueryWrapper<>();
wrapperOne.eq("parent_id","0");
List<EduSubject> oneSubjectList = baseMapper.selectList(wrapperOne);
//2 查询所有2级分类
QueryWrapper<EduSubject> wrapperTwo = new QueryWrapper<>();
wrapperTwo.ne("parent_id","0");
List<EduSubject> twoSubjectList = baseMapper.selectList(wrapperTwo);
//创建list集合，用于存储最终封装数据
List<OneSubject> finalSubjectList = new ArrayList<>();
//3、封装一级分类
for (int i = 0; i < oneSubjectList.size(); i++) {
EduSubject eduSubject = oneSubjectList.get(i);
OneSubject oneSubject = new OneSubject();
BeanUtils.copyProperties(eduSubject,oneSubject);
//在一级分类循环遍历查询所有的二级分类
//创建list集合封装每一个一级分类的二级分类
List<TwoSubject> twoFinalSubjectList = new ArrayList<>();
for (int j = 0; j < twoSubjectList.size(); j++) {
EduSubject tSubject = twoSubjectList.get(j);
if(tSubject.getParentId().equals(oneSubject.getId())){
TwoSubject twoSubject = new TwoSubject();
BeanUtils.copyProperties(tSubject,twoSubject);
twoFinalSubjectList.add(twoSubject);
}
}
//把一级下面所有的二级分类放入一级分类中
oneSubject.setChildren(twoFinalSubjectList);
finalSubjectList.add(oneSubject);
}
//4、封装二级分类
return finalSubjectList;
}


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.

import request from '@/utils/request'
export default {
//1 课程分类列表
getSubjectList() {
return request({
url: '/eduservice/subject/getAllSubject',
method: 'get'
})
}
}


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.

<template>
<div class="app-container">
<el-input v-model="filterText" placeholder="Filter keyword" style="margin-bottom:30px;" />
<el-tree ref="tree2" :data="data2" :props="defaultProps" :filter-node-method="filterNode" class="filter-tree" default-expand-all />
</div>
</template>
<script>
import subject from '@/api/edu/subject'
export default {
data() {
return {
filterText: '',
data2: [], //返回所有分类数据
defaultProps: {
# 总结
总体来说，如果你想转行从事程序员的工作，Java开发一定可以作为你的第一选择。但是不管你选择什么编程语言，提升自己的硬件实力才是拿高薪的唯一手段。
如果你以这份学习路线来学习，你会有一个比较系统化的知识网络，也不至于把知识学习得很零散。我个人是完全不建议刚开始就看《Java编程思想》、《Java核心技术》这些书籍，看完你肯定会放弃学习。建议可以看一些视频来学习，当自己能上手再买这些书看又是非常有收获的事了。
这些视频如果需要的话，可以无偿分享给大家，**点击这里即可免费领取**
![](https://s2.51cto.com/images/20210808/1628424098191732.jpg)![](https://s2.51cto.com/images/20210808/1628424098863301.jpg)

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.