java 生成树形json_Java实现树形结构的数据转Json格式
在项目中难免会用到树形结构，毕竟这是一种常用的组织架构。楼主这里整理了两个实现的版本，可以直接拿来使用，非常方便。楼主没有单独建项目，直接在以前的一个Demo上实现的。第一种，看下面代码：packagecom.johanChan.WebSocket.utils;importcom.alibaba.fastjson.JSON;importjava.util.ArrayList;importjava.
在项目中难免会用到树形结构，毕竟这是一种常用的组织架构。楼主这里整理了两个实现的版本，可以直接拿来使用，非常方便。
楼主没有单独建项目，直接在以前的一个Demo上实现的。第一种，看下面代码：
packagecom.johanChan.WebSocket.utils;
importcom.alibaba.fastjson.JSON;
importjava.util.ArrayList;
importjava.util.List;
//图层结构
public classTreeBuilder {
List nodes = new ArrayList<>();
public String buildTree(Listnodes) {
TreeBuilder treeBuilder = newTreeBuilder(nodes);
returntreeBuilder.buildJSONTree();
}
publicTreeBuilder() {}
public TreeBuilder(Listnodes) {
super();
this.nodes =nodes;
}
// 构建JSON树形结构
publicString buildJSONTree() {
List nodeTree =buildTree();
String jsonStr =JSON.toJSONString(nodeTree);
returnjsonStr;
}
// 构建树形结构
public ListbuildTree() {
List treeNodes = new ArrayList<>();
List rootNodes =getRootNodes();
for(Node rootNode : rootNodes) {
buildChildNodes(rootNode);
treeNodes.add(rootNode);
}
returntreeNodes;
}
// 递归子节点
public voidbuildChildNodes(Node node) {
List children =getChildNodes(node);
if (!children.isEmpty()) {
for(Node child : children) {
buildChildNodes(child);
}
node.setChildren(children);
}
}
// 获取父节点下所有的子节点
public ListgetChildNodes(Node pnode) {
List childNodes = new ArrayList<>();
for(Node n : nodes) {
if(pnode.getId().equals(n.getParentId())) {
childNodes.add(n);
}
}
returnchildNodes;
}
// 判断是否为根节点
public booleanrootNode(Node node) {
boolean isRootNode = true;
for(Node n : nodes) {
if(node.getParentId().equals(n.getId())) {
isRootNode = false;
break;
}
}
returnisRootNode;
}
// 获取集合中所有的根节点
public ListgetRootNodes() {
List rootNodes = new ArrayList<>();
for(Node n : nodes) {
if(rootNode(n)) {
rootNodes.add(n);
}
}
returnrootNodes;
}
public static classNode {
privateInteger id;
privateInteger parentId;
privateString name;
privateString code;
privateInteger level;
private Listchildren;
publicNode() {}
publicNode(Integer id,Integer parentId,String name,String code,Integer level){
super();
this.id =id;
this.parentId =parentId;
this.name =name;
this.code =code;
this.level =level;
}
publicInteger getId() {
returnid;
}
public voidsetId(Integer id) {
this.id =id;
}
publicInteger getParentId() {
returnparentId;
}
public voidsetParentId(Integer parentId) {
this.parentId =parentId;
}
publicString getName() {
returnname;
}
public voidsetName(String name) {
this.name =name;
}
publicString getCode() {
returncode;
}
public voidsetCode(String code) {
this.code =code;
}
publicInteger getLevel() {
returnlevel;
}
public voidsetLevel(Integer level) {
this.level =level;
}
public ListgetChildren() {
returnchildren;
}
public void setChildren(Listchildren) {
this.children =children;
}
}
}
看起来很长对吗？没关系，直接copy一下就可以使用。首先生成一个树形结构的数据：
public static ListbuildNode(){
List nodeList = new ArrayList<>();
TreeBuilder.Node node = new TreeBuilder.Node(0,-1,"地球","WORD",1);
TreeBuilder.Node node1 = new TreeBuilder.Node(1,0,"中国","CHN",1);
TreeBuilder.Node node2 = new TreeBuilder.Node(2,1,"华北区域","A",2);
TreeBuilder.Node node3 = new TreeBuilder.Node(3,1,"华南区域","B",2);
TreeBuilder.Node node4 = new TreeBuilder.Node(4,1,"华东区域","C",2);
TreeBuilder.Node node5 = new TreeBuilder.Node(5,1,"华西区域","D",2);
TreeBuilder.Node node6 = new TreeBuilder.Node(6,1,"华中区域","E",2);
TreeBuilder.Node node7 = new TreeBuilder.Node(7,6,"河南","豫",3);
TreeBuilder.Node node8 = new TreeBuilder.Node(8,6,"湖北","鄂",3);
TreeBuilder.Node node9 = new TreeBuilder.Node(9,6,"湖南","湘",3);
TreeBuilder.Node node10 = new TreeBuilder.Node(10,6,"江西","赣",3);
TreeBuilder.Node node11 = new TreeBuilder.Node(11,7,"郑州","豫A",4);
TreeBuilder.Node node12 = new TreeBuilder.Node(12,7,"开封","豫B",4);
TreeBuilder.Node node13 = new TreeBuilder.Node(13,7,"洛阳","豫C",4);
TreeBuilder.Node node14 = new TreeBuilder.Node(14,7,"南阳","豫R",4);
TreeBuilder.Node node15 = new TreeBuilder.Node(15,11,"金水区","豫A-1",5);
nodeList.add(node);
nodeList.add(node1);nodeList.add(node2);nodeList.add(node3);
nodeList.add(node4);nodeList.add(node5);nodeList.add(node6);
nodeList.add(node7);nodeList.add(node8);nodeList.add(node9);
nodeList.add(node10);nodeList.add(node11);nodeList.add(node12);
nodeList.add(node13);nodeList.add(node14);nodeList.add(node15);
returnnodeList;
}
然后调用new TreeBuilder().buildTree(nodeList)就可以返回json格式的字符串了：
packagecom.johanChan.WebSocket.controller;
importcom.alibaba.fastjson.JSON;
importcom.johanChan.WebSocket.utils.CommonUtils;
importcom.johanChan.WebSocket.utils.TreeBuilder;
importorg.springframework.stereotype.Controller;
importorg.springframework.web.bind.annotation.PathVariable;
importorg.springframework.web.bind.annotation.RequestMapping;
importorg.springframework.web.bind.annotation.ResponseBody;
importjava.util.List;
@Controller
public classTreeController {
ListnodeList ;
{
nodeList =CommonUtils.buildNode();
}
@ResponseBody
@RequestMapping("/getTreeJson")
publicString getTreeJson() {
// List nodeList = CommonUtils.buildNode();
String result =new TreeBuilder().buildTree(nodeList);
return result;
}
}
启动项目，访问/getTreeJson可以看到，页面返回了json字符串：
整理后如下：
[
{
"children":[
{
"children":[
{
"code":"A",
"id":2,
"level":2,
"name":"华北区域",
"parentId":1
},
{
"code":"B",
"id":3,
"level":2,
"name":"华南区域",
"parentId":1
},
{
"code":"C",
"id":4,
"level":2,
"name":"华东区域",
"parentId":1
},
{
"code":"D",
"id":5,
"level":2,
"name":"华西区域",
"parentId":1
},
{
"children":[
{
"children":[
{
"children":[
{
"code":"豫A-1",
"id":15,
"level":5,
"name":"金水区",
"parentId":11
}
],
"code":"豫A",
"id":11,
"level":4,
"name":"郑州",
"parentId":7
},
{
"code":"豫B",
"id":12,
"level":4,
"name":"开封",
"parentId":7
},
{
"code":"豫C",
"id":13,
"level":4,
"name":"洛阳",
"parentId":7
},
{
"code":"豫R",
"id":14,
"level":4,
"name":"南阳",
"parentId":7
}
],
"code":"豫",
"id":7,
"level":3,
"name":"河南",
"parentId":6
},
{
"code":"鄂",
"id":8,
"level":3,
"name":"湖北",
"parentId":6
},
{
"code":"湘",
"id":9,
"level":3,
"name":"湖南",
"parentId":6
},
{
"code":"赣",
"id":10,
"level":3,
"name":"江西",
"parentId":6
}
],
"code":"E",
"id":6,
"level":2,
"name":"华中区域",
"parentId":1
}
],
"code":"CHN",
"id":1,
"level":1,
"name":"中国",
"parentId":0
}
],
"code":"WORD",
"id":0,
"level":1,
"name":"地球",
"parentId":-1
}
]
第一种方法完成，下面是第二种实现，首先建立一个类：
package com.johanChan.WebSocket.utils;
import java.util.ArrayList;
import java.util.List;
public class Tree {
/**
* 节点ID
*/
private Integer id;
/**
* 显示节点文本
*/
private String text;
/**
* 父ID
*/
private Integer parentId;
private Integer level;
/**
* 节点的子节点
*/
// private List> nodes = new ArrayList>();
private List> nodes = null;
public Tree() {}
public Tree(Integer id,Integer parentId,String text,Integer level){
super();
this.id = id;
this.text = text;
this.parentId = parentId;
this.level = level;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
public Integer getParentId() {
return parentId;
}
public void setParentId(Integer parentId) {
this.parentId = parentId;
}
public Integer getLevel() {
return level;
}
public void setLevel(Integer level) {
this.level = level;
}
public List> getNodes() {
if(nodes==null){
nodes = new ArrayList>();
}
return nodes;
}
public void setNodes(List> nodes) {
this.nodes = nodes;
}
}
然后对Tree进行排序：
packagecom.johanChan.WebSocket.utils;
importjava.util.ArrayList;
importjava.util.List;
public classBuildTree {
public static List> build(List>nodes) {
if (nodes == null) {
return null;
}
List> topNodes = new ArrayList<>();
for (Treechildren : nodes) {
String pid =children.getParentId();
if (pid.equals(children.getId() )) {
topNodes.add(children);
continue;
}
for (Treeparent : nodes) {
String id =parent.getId();
if (id != null &&id.equals(pid)) {
parent.getNodes().add(children);
}
}
}
returntopNodes;
}
}
然后生成数据：
public static List>buildTree(){
List> treeList = new ArrayList<>();
Tree tree = new Tree(0,0,"地球",1);
Tree tree1= new Tree(1,0,"中国",1);
Tree tree2= new Tree(2,1,"华北区域",2);
Tree tree3= new Tree(3,1,"华南区域",2);
Tree tree4= new Tree(4,1,"华东区域",2);
Tree tree5= new Tree(5,1,"华西区域",2);
Tree tree6= new Tree(6,1,"华中区域",2);
Tree tree7= new Tree(7,6,"河南",3);
Tree tree8= new Tree(8,6,"湖北",3);
Tree tree9= new Tree(9,6,"湖南",3);
Tree tree10= new Tree(10,6,"江西",3);
Tree tree11= new Tree(11,7,"郑州",4);
Tree tree12= new Tree(12,7,"开封",4);
Tree tree13= new Tree(13,7,"洛阳",4);
Tree tree14= new Tree(14,7,"南阳",4);
Tree tree15= new Tree(15,11,"金水区",5);
treeList.add(tree);
treeList.add(tree1);treeList.add(tree2);treeList.add(tree3);
treeList.add(tree4);treeList.add(tree5);treeList.add(tree6);
treeList.add(tree7);treeList.add(tree8);treeList.add(tree9);
treeList.add(tree10);treeList.add(tree11);treeList.add(tree12);
treeList.add(tree13);treeList.add(tree14);treeList.add(tree15);returntreeList;
}
调用方法：
packagecom.johanChan.WebSocket.controller;importcom.alibaba.fastjson.JSON;importcom.johanChan.WebSocket.utils.BuildTree;importcom.johanChan.WebSocket.utils.CommonUtils;importcom.johanChan.WebSocket.utils.Tree;importcom.johanChan.WebSocket.utils.TreeBuilder;importorg.springframework.stereotype.Controller;importorg.springframework.web.bind.annotation.PathVariable;importorg.springframework.web.bind.annotation.RequestMapping;importorg.springframework.web.bind.annotation.ResponseBody;importjava.util.List;
@Controllerpublic classTreeController {
ListnodeList ;
List>treeList;
{
nodeList=CommonUtils.buildNode();
treeList=CommonUtils.buildTree();
}
@ResponseBody
@RequestMapping("/getTreeJson")publicString getTreeJson() {//List nodeList = CommonUtils.buildNode();//String result = CommonUtils.buildTree(nodeList);
List> resultList =BuildTree.build(treeList);
String result=JSON.toJSONString(resultList);returnresult;
}}
返回数据如下：
整理后：
[
{"id":0,"level":1,"nodes":[
{"id":1,"level":1,"nodes":[
{"id":2,"level":2,"nodes":[
],"parentId":1,"text":"华北区域"},
{"id":3,"level":2,"nodes":[
],"parentId":1,"text":"华南区域"},
{"id":4,"level":2,"nodes":[
],"parentId":1,"text":"华东区域"},
{"id":5,"level":2,"nodes":[
],"parentId":1,"text":"华西区域"},
{"id":6,"level":2,"nodes":[
{"id":7,"level":3,"nodes":[
{"id":11,"level":4,"nodes":[
{"id":15,"level":5,"nodes":[
],"parentId":11,"text":"金水区"}
],"parentId":7,"text":"郑州"},
{"id":12,"level":4,"nodes":[
],"parentId":7,"text":"开封"},
{"id":13,"level":4,"nodes":[
],"parentId":7,"text":"洛阳"},
{"id":14,"level":4,"nodes":[
],"parentId":7,"text":"南阳"}
],"parentId":6,"text":"河南"},
{"id":8,"level":3,"nodes":[
],"parentId":6,"text":"湖北"},
{"id":9,"level":3,"nodes":[
],"parentId":6,"text":"湖南"},
{"id":10,"level":3,"nodes":[
],"parentId":6,"text":"江西"}
],"parentId":1,"text":"华中区域"}
],"parentId":0,"text":"中国"}
],"parentId":0,"text":"地球"}
]
View Code
OK！以上两种方法都比较有通用性，把自己的数据整理后调用就可以了。
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