list转树形结构

不念不忘少年蓝@ 2023-06-28 06:22 104阅读 0赞

### 先上效果 ###

![在这里插入图片描述][20200107203807731.png]

//实体类
    class TreeNode{ 
    	String id;
    	String name;
    	String pId;
    	List<TreeNode> childRen=new ArrayList<>();
    
    	public String getId() { 
    		return id;
    	}
    
    	public void setId(String id) { 
    		this.id = id;
    	}
    
    	public String getName() { 
    		return name;
    	}
    
    	public void setName(String name) { 
    		this.name = name;
    	}
    
    	public String getpId() { 
    		return pId;
    	}
    
    	public void setpId(String pId) { 
    		this.pId = pId;
    	}
    
    	public List<TreeNode> getChildRen() { 
    		return childRen;
    	}
    
    	public void setChildRen(List<TreeNode> childRen) { 
    		this.childRen = childRen;
    	}
    
    	public TreeNode() { 
    	}
    
    	public TreeNode(String id, String name, String pId) { 
    		this.id = id;
    		this.name = name;
    		this.pId = pId;
    	}
    
    	@Override
    	public String toString() { 
    		return "TreeNode{" +
    				"id='" + id + '\'' +
    				", name='" + name + '\'' +
    				", pId='" + pId + '\'' +
    				", childRen=" + childRen +
    				'}';
    	}
    }

@Test
    	public void test() { 
    		//造list数据
    		List<TreeNode> list = new ArrayList<>();
    		TreeNode treeNode = new TreeNode("1","一组","0");
    		TreeNode treeNode1 = new TreeNode("2","二组","0");
    		TreeNode treeNode3 = new TreeNode("11","一组第一","1");
    		TreeNode treeNode4 = new TreeNode("21","二组第一","2");
    		TreeNode treeNode5 = new TreeNode("12","一组第一","1");
    		TreeNode treeNode6 = new TreeNode("22","二组第一","2");
    		TreeNode treeNode7 = new TreeNode("3","3组","0");
    		list.add(treeNode4);
    		list.add(treeNode5);
    		list.add(treeNode6);
    		list.add(treeNode7);
    		list.add(treeNode);
    		list.add(treeNode1);
    		list.add(treeNode3);
    
            //=======逻辑处理=========
    		Set<TreeNode> resultList = new HashSet<>();//用于接收返回的数据
    		HashMap<String,TreeNode> hashMap = new HashMap<>();
    		for (TreeNode node : list) { 
    			resultList.add(node);
    			hashMap.put(node.getId(),node);
    		}
    		for(Map.Entry<String, TreeNode> entry : hashMap.entrySet()){ 
    			//String mapKey = entry.getKey();
    			TreeNode node = entry.getValue();
    			String pId = node.getpId();//父id
    			if(hashMap.containsKey(pId)){ //将子节点移动到对应父节点下面
    				resultList.remove(node);
    				hashMap.get(pId).getChildRen().add(node);
    				resultList.add(hashMap.get(pId));
    			}
    		}
    		//输出查看结果
    		System.out.println(JSONArray.toJSON(resultList));
    	}

[20200107203807731.png]: https://img-blog.csdnimg.cn/20200107203807731.png