java递归无级树输出json格式

由于项目需要将数据库中的一个层级表转换成json格式输出，在网上找了很久都没有找开合适的内容，要不是代码太复杂，就是不符合需求，所以就自己用递归写了一个无级树的代码。代码很简单就两个类一个TreeNode.java 和一个测试类Test.java(可直接运行)

在运行之前需要以下公共类:

commons-beanutils.jar

commons-collections.jar

commons-lang.jar

commons-logging.jar

ezmorph-1.0.6.jar

json-lib-2.3-jdk15.jar

package com.test;
import java.util.ArrayList;
public class TreeNode {
    private String id;
    private String pid;
    private String name;
    private String remark;
    private ArrayList<TreeNode> children = new ArrayList<TreeNode>();
    public TreeNode(String id, String pid, String name, String remark) {
        this.id = id;
        this.pid = pid;
        this.name = name;
        this.remark = remark;
    }
    public void add(TreeNode node) {//递归添加节点
        if ("0".equals(node.pid)) {
            this.children.add(node);
        } else if (node.pid.equals(this.id)) {
            this.children.add(node);
        } else {
            for (TreeNode tmp_node : children) {
                tmp_node.add(node);
            }
        }
    }
    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 getRemark() {
        return remark;
    }
    public void setRemark(String remark) {
        this.remark = remark;
    }
    public ArrayList<TreeNode> getChildren() {
        return children;
    }
    public void setChildren(ArrayList<TreeNode> children) {
        this.children = children;
    }
}

测试类 Test.java

package com.test;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
public class Test {
    public static void main(String[] args) {
        TreeNode root = new TreeNode("0", "0", "000000", "00JJJ");
        TreeNode node = null;
        node = new TreeNode("1", "0", "111111", "11AAA");
        root.add(node);
        node = new TreeNode("2", "0", "222222", "11BBB");
        root.add(node);
        node = new TreeNode("3", "2", "333333", "11CCC");
        root.add(node);
        // JSONObject obj = JSONObject.fromObject(root);//有根
        JSONArray obj = JSONArray.fromObject(root.getChildren());// 不要根
        System.out.println(obj.toString());
    }
}