生成树结构简洁版记录

@Override
public List<DeviceCategoryDictEntity> getDeviceCategoryTree() {

    //查询设备类型字典表的所有数据
    List<DeviceCategoryDictEntity> allList = deviceCategoryDictDao.selectList(new QueryWrapper<>());

    //生成树结构
    return allList.stream().filter(s -> s.getPId() == null).map(item -> {
        item.setChildren(getChild(item.getId(), allList));
        return item;
    }).collect(Collectors.toList());
}

public List<DeviceCategoryDictEntity> getChild(String id, List<DeviceCategoryDictEntity> allList) {
    List<DeviceCategoryDictEntity> collect = allList.stream().filter(item -> id.equals(item.getPId())).collect(Collectors.toList());
    return collect;
}