java-树形结构的list，转化为树形结构

举例部门级别

//节点对象类
package com.test;

import java.util.List;
/**
 * ClassName: TestMode 
 * @Description: 测试对象
 */
public class TestMode {

	/** 节点id */
	private String id;
	/** 节点名称 */
	private String name;
	/** 父节点id */
	private String parentId;
	/** 节点下的子节点 */
	private List children;
	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 getParentId() {
		return parentId;
	}
	public void setParentId(String parentId) {
		this.parentId = parentId;
	}
	public List getChildren() {
		return children;
	}
	public void setChildren(List children) {
		this.children = children;
	}
	@Override
	public String toString() {
		return "{"+"id=" + id + ", name=" + name + ", parentId=" + parentId + ", children=" + children+"}";
	}
	
	
}

测试类

package com.test;

import java.util.ArrayList;
import java.util.List;
/**
 * @Description: 转化List为树形结构
 */
public class ListToTreeUtil {

	public static void main(String[] args) {
		List list = new ArrayList();
		TestMode testMode1 = new TestMode();
		testMode1.setId("-1");
		testMode1.setName("父节点");
		testMode1.setParentId("0");//其实-1节点没有父节点，只是为了方便
		TestMode testMode2 = new TestMode();
		testMode2.setId("1");
		testMode2.setName("第一级节点1");
		testMode2.setParentId("-1");
		TestMode testMode3 = new TestMode();
		testMode3.setId("2");
		testMode3.setName("第一级节点2");
		testMode3.setParentId("-1");
		TestMode testMode4 = new TestMode();
		testMode4.setId("11");
		testMode4.setName("第二级节点11");
		testMode4.setParentId("1");
		TestMode testMode5 = new TestMode();
		testMode5.setId("111");
		testMode5.setName("第三级节点111");
		testMode5.setParentId("11");
		TestMode testMode6 = new TestMode();
		testMode6.setId("21");
		testMode6.setName("第二级级节点21");
		testMode6.setParentId("2");
		list.add(testMode1);
		list.add(testMode2);
		list.add(testMode3);
		list.add(testMode4);
		list.add(testMode5);
		list.add(testMode6);
		System.out.println("处理前的数据格式:"+ list.toString());
		list = getDeptTree(list,"0");
		System.out.println("处理后的数据格式:"+ list.toString());
	}
	
	public static List getDeptTree(List list,String pid){
		List result =  new ArrayList();
		List temp =  new ArrayList();
		for(TestMode entity : list){
			if(entity.getParentId().equals(pid)){
				TestMode deptScopeMode = new TestMode();
				deptScopeMode.setId(entity.getId());
				deptScopeMode.setName(entity.getName());
				deptScopeMode.setParentId(entity.getParentId());
				temp = getDeptTree(list,entity.getId());
				if(temp.size() > 0){
					deptScopeMode.setChildren(temp);
				}
				result.add(deptScopeMode);
			}
		}
		return result;
	}
}

处理签的数据格式：

[{
	id = -1,
	name = 父节点,
	parentId = 0,
	children = null
}, {
	id = 1,
	name = 第一级节点1,
	parentId = -1,
	children = null
}, {
	id = 2,
	name = 第一级节点2,
	parentId = -1,
	children = null
}, {
	id = 11,
	name = 第二级节点11,
	parentId = 1,
	children = null
}, {
	id = 111,
	name = 第三级节点111,
	parentId = 11,
	children = null
}, {
	id = 21,
	name = 第二级级节点21,
	parentId = 2,
	children = null
}]

处理后的数据格式：

[{
	id = -1,
	name = 父节点,
	parentId = 0,
	children = [{
		id = 1,
		name = 第一级节点1,
		parentId = -1,
		children = [{
			id = 11,
			name = 第二级节点11,
			parentId = 1,
			children = [{
				id = 111,
				name = 第三级节点111,
				parentId = 11,
				children = null
			}]
		}]
	}, {
		id = 2,
		name = 第一级节点2,
		parentId = -1,
		children = [{
			id = 21,
			name = 第二级级节点21,
			parentId = 2,
			children = null
		}]
	}]
}]