java中查询部门表，转换为树形json

Question

java中查询部门表，转换为树形json，最终需要使用Dtree 在前端展示树形结构

数据结构如下图

不管用什么方式，最终希望得到json格式为：

{
    "id": "1",
    "name": "GM",
    "Children": [{
            "id": "22",
            "name": "PM",
            "Children": [{
                "id": "67",
                "name": "MO",
                "Children": [{}]
            }]
        },

        {
            "id": "23",
            "name": "PD",
            "Children": [{}]
        },
        {
            "id": "24",
            "name": "PE",
            "Children": [{}]
        }
    ]
 }

求大神指点

Answer 1

部门类

public class Department {

    private String id;

    private String name;

    private String pid;

    public Department(String id, String name, String pid) {
        super();
        this.id = id;
        this.name = name;
        this.pid = pid;
    }

    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;
    }
}

节点类

package com.kevin;

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

public class TreeNode   implements Serializable{

    private String id;

    private String name;

    private List<TreeNode> children=new ArrayList<TreeNode>();

    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 List<TreeNode> getChildren() {
        return children;
    }

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


}

生成过程

public static void main(String[] args) {

        List<Department> dList = new ArrayList<>();

        dList.add(new Department("1","GM","0"));
        dList.add(new Department("22","PM","1"));
        dList.add(new Department("21","R7D","1"));
        dList.add(new Department("27","STD","21"));

        Map<String, List<TreeNode>> map=new HashMap<String, List<TreeNode>>();
        TreeNode node=null;
        Set<String> idSet=new HashSet<>();
        for (Department department : dList) {
            if(!idSet.contains(department.getId())) {
                node = new TreeNode();
                node.setId(department.getId());
                node.setName(department.getName());

                if(map.get(department.getPid())==null) {
                    map.put(department.getPid(), new ArrayList<>());
                }

                map.get(department.getPid()).add(node);

                idSet.add(department.getId());
            }
        }

        Iterator<String> it=map.keySet().iterator();
        String id=null;
        while(it.hasNext()) {
            id = it.next();
            List<TreeNode> childeNodes=map.get(id);
            for (TreeNode treeNode : childeNodes) {
                if(map.get(treeNode.getId())!=null) {
                    treeNode.getChildren().addAll(map.get(treeNode.getId()));
                }
            }
        }

        //System.out.println(map.get("0").toString());
        System.out.println(JSONObject.toJSON(map.get("0")));

    }

测试结果

[
    {
        "children":[
            {
                "children":[

                ],
                "name":"PM",
                "id":"22"
            },
            {
                "children":[
                    {
                        "children":[

                        ],
                        "name":"STD",
                        "id":"27"
                    }
                ],
                "name":"R7D",
                "id":"21"
            }
        ],
        "name":"GM",
        "id":"1"
    }
]

些许不一样，按需参考