递归查找子菜单

package com.zzc.product.service.impl;

import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.zzc.common.utils.PageUtils;
import com.zzc.common.utils.Query;

import com.zzc.product.dao.CategoryDao;
import com.zzc.product.entity.CategoryEntity;
import com.zzc.product.service.CategoryService;


@Service("categoryService")
public class CategoryServiceImpl extends ServiceImpl<CategoryDao, CategoryEntity> implements CategoryService {

    @Override
    public PageUtils queryPage(Map<String, Object> params) {
        IPage<CategoryEntity> page = this.page(
                new Query<CategoryEntity>().getPage(params),
                new QueryWrapper<CategoryEntity>()
        );

        return new PageUtils(page);
    }

    @Override
    public List<CategoryEntity> listTree() {
        //先查询所有
        List<CategoryEntity> categoryAll = baseMapper.selectList(null);
        //在树形展示
        //能确定的就是一级菜单的parent_cid=0
        List<CategoryEntity> list1 =null;
        //stream流式操作
        list1 = categoryAll.stream().filter(category -> category.getParentCid() == 0).collect(Collectors.toList());
        //二级菜单
        list1.stream().map((menu)->{
            menu.setChildren(getChildren(menu,categoryAll));
            return menu;
        }).collect(Collectors.toList());;

        return list1;
    }

    @Override
    public void removeMuneByIds(List<Long> asList) {
        baseMapper.deleteBatchIds(asList);
    }

    @Override
    public Long[] findCatelogPath(Long catelogId) {
        CategoryEntity categoryEntity = baseMapper.selectById(catelogId);
        List<Long> path = new ArrayList<>();
        path.add(categoryEntity.getCatId());
        while (categoryEntity.getParentCid() != 0){
            path.add(categoryEntity.getParentCid());
            categoryEntity = baseMapper.selectById(categoryEntity.getParentCid());
        }
        Collections.reverse(path);
        return path.toArray(new Long[path.size()]);
    }

    /**
     * 递归查找子菜单
     * @return
     */
    private List<CategoryEntity> getChildren(CategoryEntity curCategory,List<CategoryEntity> allCategory){
        List<CategoryEntity> collect = allCategory.stream().filter((menu)-> {
            return menu.getParentCid().equals(curCategory.getCatId());
        }).map((menu)-> {
          menu.setChildren(getChildren(menu,allCategory));
          return menu;
        }).collect(Collectors.toList());
        return collect;
    }
}