1 public List<CategoryEntity> treeList() {
2 List<CategoryEntity> categoryEntities = baseMapper.selectList(null);
3
4 List<CategoryEntity> treeList = categoryEntities.stream()
5 // 查找一级分类
6 .filter(categoryEntity -> categoryEntity.getParentCid() == 0)
7 // 递归设置二级分类
8 .map(categoryEntity -> {
9 categoryEntity.setChildren(getChildrens(categoryEntity, categoryEntities));
10 return categoryEntity;
11 })
12 // 根据sort字段进行排序
13 .sorted((categoryEntity1, categoryEntity2) -> {
14 return (categoryEntity1.getSort() == null ? 0 : categoryEntity1.getSort()) - (categoryEntity2.getSort() == null ? 0 : categoryEntity2.getSort());
15 })
16 // 收集处理完成的数据{parent: children[]}
17 .collect(Collectors.toList());
18 return treeList;
19 }
20
21 private List<CategoryEntity> getChildrens(CategoryEntity root, List<CategoryEntity> categoryEntities) {
22 /**
23 CategoryEntity root 当前节点
24 List<CategoryEntity> categoryEntities 要进行匹配的集合
25 */
26 List<CategoryEntity> children = categoryEntities.stream()
27 .filter(categoryEntity -> categoryEntity.getParentCid() == root.getCatId())
28 .map(categoryEntity -> {
29 categoryEntity.setChildren(getChildrens(categoryEntity, categoryEntities));
30 return categoryEntity;
31 })
32 .sorted((categoryEntity1, categoryEntity2) -> {
33 return (categoryEntity1.getSort() == null ? 0 : categoryEntity1.getSort()) - (categoryEntity2.getSort() == null ? 0 : categoryEntity2.getSort());
34 })
35 .collect(Collectors.toList());
36 return children;
37 }
