树形结构的json数据源，

最新推荐文章于 2024-04-30 11:32:30 发布

wanghuanhuanlifeng

最新推荐文章于 2024-04-30 11:32:30 发布

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文章标签： json list iterator string extjs class

本文介绍了一种使用Java实现的递归方法来构建JSON树结构。通过递归遍历Node对象列表，根据父节点ID与子节点ID的关系构建树形结构，并最终输出符合Extjs JSON格式要求的字符串。该方法适用于需要将层级数据转换为树形结构的场景。

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[b]转[/b]

package test;

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

import com.baihe.entity.Node;

public class bd {

List nodeList =new ArrayList();
bd(){//构造方法里初始化模拟List
         Node node1 = new Node("01","0");
         Node node2 = new Node("0102","01");
         Node node3 = new Node("0103","01");
         Node node4 = new Node("010201","0102");
         Node node5 = new Node("010202","0102");

         nodeList.add(node1);
         nodeList.add(node2);
         nodeList.add(node3);
         nodeList.add(node4);
         //nodeList.add(node5);

     }
     StringBuffer returnStr=new StringBuffer();
     public void recursionFn(List list , Node node){
         if(hasChild(list,node)){
             returnStr.append("{id:");
             returnStr.append(node.getId());
             returnStr.append(",parentId:");
             returnStr.append(node.getParentId());
             returnStr.append(",children:[");
             List childList = getChildList(list,node);
             Iterator it = childList.iterator();
             while(it.hasNext()){
                 Node n = (Node)it.next();
                 recursionFn(list,n);
             }
             returnStr.append("]},");
         }else{
             returnStr.append("{id:");
             returnStr.append(node.getId());
             returnStr.append(",parentId:");
             returnStr.append(node.getParentId());
             returnStr.append(",leaf:true},");
         }

     }
     public boolean hasChild(List list, Node node){ //判断是否有子节点
         return getChildList(list,node).size()>0?true:false;
     }
     public List getChildList(List list , Node node){ //得到子节点列表
         List li = new ArrayList();
         Iterator it = list.iterator();
         while(it.hasNext()){
             Node n = (Node)it.next();
             if(n.getParentId().endsWith(node.getId())){
                 li.add(n);
             }
         }
         return li;
     }
     public String modifyStr(String returnStr){//修饰一下才能满足Extjs的Json格式
         return ("["+returnStr+"]").replaceAll(",]", "]");

     }
     public static void main(String[] args) {
     bd r = new bd();
         r.recursionFn(r.nodeList, new Node("01","0"));
         System.out.println(r.modifyStr(r.returnStr.toString()));
     }
}