Tree结构生成工具类

快速导航

• [数据结构] 数据结构
• [具体实现] 具体实现
• [测试用例] 测试用例

数据结构

CategoryTreeNode

Tree结构数据类型封装

Tree结构数据类型封装，代码如下:

package com.boot.component.tree.category;

import java.util.List;

public class CategoryTreeNode {

    private Integer id;

    private Integer parentId;

    private String name;

    private List children;

    public CategoryTreeNode(Integer id, String name, Integer parentId) {
        this.id = id;
        this.parentId = parentId;
        this.name = name;
    }

    public CategoryTreeNode(Integer id, String name, CategoryTreeNode parent) {
        this.id = id;
        this.parentId = parent.getId();
        this.name = name;
    }

    public Integer getParentId() {
        return parentId;
    }

    public void setParentId(Integer parentId) {
        this.parentId = parentId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public List getChildren() {
        return children;
    }

    public void setChildren(List children) {
        this.children = children;
    }

    @Override
    public String toString() {
        return "CategoryTreeNode{" + "id='" + id + '\'' + ", parentId='" + parentId + '\'' + ", name='" + name + '\''
                + ", children=" + children + '}';
    }

}

具体实现

CategoryTreeBuilder

Tree结构数据生成

Tree结构数据生成类封装，代码如下:

package com.boot.component.tree.category;

import java.util.ArrayList;
import java.util.List;

import com.xiaoleilu.hutool.util.ObjectUtil;

public class CategoryTreeBuilder {

    /**
     * 使用递归方法建树
     * @param categoryList 传入的树节点列表
     * @return
     */
    public static List buildTree(List categoryList, Integer pid) {
        List treeList = new ArrayList<>();
        categoryList.forEach(categoryTreeNode -> {
            if (categoryTreeNode.getParentId() == pid) {
                categoryTreeNode.setChildren(buildTree(categoryList, categoryTreeNode.getId()));
                treeList.add(categoryTreeNode);
            }
        });
        return treeList;
    }

    /**
     * 两层循环实现建树
     * @param treeNodes 传入的树节点列表
     * @return
     */
    public static List bulid(List treeNodes) {

        List trees = new ArrayList();

        for (CategoryTreeNode treeNode : treeNodes) {

            if (0 == treeNode.getParentId()) {
                trees.add(treeNode);
            }

            for (CategoryTreeNode it : treeNodes) {
                if (ObjectUtil.equal(it.getParentId(), treeNode.getId())) {
                    if (treeNode.getChildren() == null) {
                        treeNode.setChildren(new ArrayList());
                    }
                    treeNode.getChildren().add(it);
                }
            }
        }
        return trees;
    }

    /**
     * 使用递归方法建树
     * @param treeNodes
     * @return
     */
    public static List buildByRecursive(List treeNodes) {
        List trees = new ArrayList();
        for (CategoryTreeNode treeNode : treeNodes) {
            if (0 == treeNode.getParentId()) {
                trees.add(findChildren(treeNode, treeNodes));
            }
        }
        return trees;
    }

    /**
     * 递归查找子节点
     * @param treeNodes
     * @return
     */
    public static CategoryTreeNode findChildren(CategoryTreeNode treeNode, List treeNodes) {
        for (CategoryTreeNode it : treeNodes) {
            if (treeNode.getId().equals(it.getParentId())) {
                if (treeNode.getChildren() == null) {
                    treeNode.setChildren(new ArrayList());
                }
                treeNode.getChildren().add(findChildren(it, treeNodes));
            }
        }
        return treeNode;
    }

}

测试用例

TestCategoryTreeNodeUtil

main方法测试运行结果

package com.boot.test;

import java.util.ArrayList;
import java.util.List;

import com.boot.component.tree.category.CategoryTreeBuilder;
import com.boot.component.tree.category.CategoryTreeNode;

public class TestCategoryTreeNodeUtil {

    public static void main(String[] args) {

        CategoryTreeNode treeNode1 = new CategoryTreeNode(1, "广州", 0);
        CategoryTreeNode treeNode2 = new CategoryTreeNode(2, "深圳", 0);

        CategoryTreeNode treeNode3 = new CategoryTreeNode(3, "天河区", 1);
        CategoryTreeNode treeNode4 = new CategoryTreeNode(4, "越秀区", 1);
        CategoryTreeNode treeNode5 = new CategoryTreeNode(5, "黄埔区", 1);
        CategoryTreeNode treeNode6 = new CategoryTreeNode(6, "石牌", 2);
        CategoryTreeNode treeNode7 = new CategoryTreeNode(7, "百脑汇", 2);

        List list = new ArrayList();

        list.add(treeNode1);
        list.add(treeNode2);
        list.add(treeNode3);
        list.add(treeNode4);
        list.add(treeNode5);
        list.add(treeNode6);
        list.add(treeNode7);

        // List trees = CategoryTreeBuilder.bulid(list);
        // List trees_ = CategoryTreeBuilder.buildTree(list, null);
        List trees = CategoryTreeBuilder.buildTree(list, 1);
        System.out.println(trees);
    }

}