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发现了画图对于理解的帮助了
解决了一直以来困扰我的树状结构问题, 开心
贴上自己的代码

    public List<District> getDistricts(String tenant) {
        List<District> flatDistricts = mapper.getDistricts(tenant);
        //获取孩子键值对
        Map<String, List<District>> childGroup = flatDistricts.stream().filter(f -> f.getParentCode() != null).collect(Collectors.groupingBy(District::getParentCode));
        //获取所有父元素
        List<District> districts = flatDistricts.stream().filter(f->f.getParentCode() == null).collect(Collectors.toList());
        ArrayList<District> parents = new ArrayList<>(districts);
        for (int i = 0; i < parents.size(); i++) {
            District currentParentDistrict = parents.get(i);
            List<District> childrenDistricts = childGroup.get(currentParentDistrict.getCode());
            if(childrenDistricts != null) {
                currentParentDistrict.setChildren(childrenDistricts);
                parents.addAll(childrenDistricts);
            }
        }
        return districts;
    }

本文标签: 树状算法结构