java编程两种树形菜单结构的转换代码

package com.zzj.tree;
public class SingleTreeNode 
	private int id;
	private int pId;
	private String name;
	public SingleTreeNode() 
	
	public SingleTreeNode(int id, int pId, String name) 
		this.id = id;
		this.pId = pId;
		this.name = name;
	
	public int getId() 
		return id;
	
	public void setId(int id) 
		this.id = id;
	
	public int getpId() 
		return pId;
	
	public void setpId(int pId) 
		this.pId = pId;
	
	public String getName() 
		return name;
	
	public void setName(String name) 
		this.name = name;
	
	@Override 
	  public String toString() 
		return "SingleTreeNode id=" + id + ", pId=" + pId + ", name=" + name + "";
	

package com.zzj.tree;
import java.util.List;
public class MultiTreeNode 
	private int id;
	private String name;
	private List<MultiTreeNode> children;
	public MultiTreeNode() 
	
	public MultiTreeNode(int id, String name) 
		this.id = id;
		this.name = name;
	
	public MultiTreeNode(int id, String name, List<MultiTreeNode> children) 
		this.id = id;
		this.name = name;
		this.children = children;
	
	public int getId() 
		return id;
	
	public void setId(int id) 
		this.id = id;
	
	public String getName() 
		return name;
	
	public void setName(String name) 
		this.name = name;
	
	public List<MultiTreeNode> getChildren() 
		return children;
	
	public void setChildren(List<MultiTreeNode> children) 
		this.children = children;
	
	@Override 
	  public String toString() 
		return "MultiTreeNode id=" + id + ", name=" + name + ", children=" + children + "";
	

package com.zzj.tree;
import java.util.ArrayList;
import java.util.List;
public class ToMultiTreeTransformer 
	private List<SingleTreeNode> singleTreeNodes;
	private List<MultiTreeNode> multiTreeNodes = new ArrayList<>();
	public ToMultiTreeTransformer(List<SingleTreeNode> singleTreeNodes) 
		this.singleTreeNodes = singleTreeNodes;
	
	public List<MultiTreeNode> transform()
		// 先找出所有的根节点 
		for (int i = 0; i < singleTreeNodes.size(); i++) 
			SingleTreeNode singleTreeNode = singleTreeNodes.get(i);
			Boolean isRoot = true;
			for (int j = 0; j < singleTreeNodes.size(); j++) 
				SingleTreeNode temp = singleTreeNodes.get(j);
				if (singleTreeNode.getpId() == temp.getId()) 
					isRoot = false;
					break;
				
			
			if (isRoot) 
				MultiTreeNode multiTreeNode = new MultiTreeNode(singleTreeNode.getId(),  
				            singleTreeNode.getName());
				multiTreeNodes.add(multiTreeNode);
			
		
		// 设置子节点 
		for (int i = 0; i < multiTreeNodes.size(); i++) 
			MultiTreeNode multiTreeNode = multiTreeNodes.get(i);
			setChildren(multiTreeNode);
		
		return multiTreeNodes;
	
	/** 
   * 设置子节点 
   * @param multiTreeNode 
   */
	private void setChildren(MultiTreeNode multiTreeNode)
		for (int j = 0; j < singleTreeNodes.size(); j++) 
			SingleTreeNode temp = singleTreeNodes.get(j);
			if (temp.getpId() == multiTreeNode.getId()) 
				MultiTreeNode child = new MultiTreeNode(temp.getId(),  
				            temp.getName());
				List<MultiTreeNode> children = multiTreeNode.getChildren();
				if (children == null) 
					children = new ArrayList<>();
					multiTreeNode.setChildren(children);
				
				children.add(child);
				setChildren(child);
			
		
	

package com.zzj.tree;
import java.util.ArrayList;
import java.util.List;
public class ToSingleTreeTransformer 
	private List<MultiTreeNode> multiTreeNodes;
	private List<SingleTreeNode> singleTreeNodes = new ArrayList<>();
	public ToSingleTreeTransformer(List<MultiTreeNode> multiTreeNodes) 
		this.multiTreeNodes = multiTreeNodes;
	
	public List<SingleTreeNode> transform()
		// 先获取根节点 
		for (int i = 0; i < multiTreeNodes.size(); i++) 
			MultiTreeNode multiTreeNode = multiTreeNodes.get(i);
			SingleTreeNode singleTreeNode = new SingleTreeNode(multiTreeNode.getId(),  
			          0, multiTreeNode.getName());
			singleTreeNodes.add(singleTreeNode);
		
		// 获取子节点 
		for (int i = 0; i < multiTreeNodes.size(); i++) 
			MultiTreeNode multiTreeNode = multiTreeNodes.get(i);
			getChildren(multiTreeNode);
		
		return singleTreeNodes;
	
	/** 
   * 获取子节点 
   * @param multiTreeNode 
   */
	private void getChildren(MultiTreeNode multiTreeNode)
		for (int i = 0; i < singleTreeNodes.size(); i++) 
			SingleTreeNode temp = singleTreeNodes.get(i);
			if (multiTreeNode.getId() == temp.getId()) 
				List<MultiTreeNode> children = multiTreeNode.getChildren();
				if (children != null) 
					for (int j = 0; j < children.size(); j++) 
						MultiTreeNode child = children.get(j);
						SingleTreeNode singleTreeNode = new SingleTreeNode(child.getId(),  
						                multiTreeNode.getId(), child.getName());
						singleTreeNodes.add(singleTreeNode);
						getChildren(child);
					
				
			
		
	

package com.zzj.tree;
import java.util.ArrayList;
import java.util.List;
public class TreeTransformerTest 
	private final static List<SingleTreeNode> SINGLE_TREE = new ArrayList<SingleTreeNode>();
	static 
		SingleTreeNode China = new SingleTreeNode(1, 0, "中国");
		SINGLE_TREE.add(China);
		SingleTreeNode Hunan = new SingleTreeNode(2, 1, "湖南");
		SINGLE_TREE.add(Hunan);
		SingleTreeNode Changsha = new SingleTreeNode(3, 2, "长沙");
		SINGLE_TREE.add(Changsha);
		SingleTreeNode Hubei = new SingleTreeNode(4, 1, "湖北");
		SINGLE_TREE.add(Hubei);
		SingleTreeNode Wuhan = new SingleTreeNode(5, 4, "武汉");
		SINGLE_TREE.add(Wuhan);
		SingleTreeNode America = new SingleTreeNode(6, 0, "美国");
		SINGLE_TREE.add(America);
		SingleTreeNode California = new SingleTreeNode(7, 6, "加利福尼亚");
		SINGLE_TREE.add(California);
		SingleTreeNode LosAngeles = new SingleTreeNode(8, 7, "洛杉矶");
		SINGLE_TREE.add(LosAngeles);
	
	public static void main(String args) throws Exception 
		ToMultiTreeTransformer multiTreeTransformer = new ToMultiTreeTransformer(SINGLE_TREE);
		List<MultiTreeNode> multiTreeNodes = multiTreeTransformer.transform();
		System.out.println(multiTreeNodes);
		ToSingleTreeTransformer singleTreeTransformer = new ToSingleTreeTransformer(multiTreeNodes);
		List<SingleTreeNode> singleTreeNodes = singleTreeTransformer.transform();
		System.out.println(singleTreeNodes);
	

MultiTreeNode id=1, name=中国, children=MultiTreeNode id=2, name=湖南, children=MultiTreeNode id=3, name=长沙, children=null, MultiTreeNode id=4, name=湖北, children=MultiTreeNode id=5, name=武汉, children=null, MultiTreeNode id=6, name=美国, children=MultiTreeNode id=7, name=加利福尼亚, children=MultiTreeNode id=8, name=洛杉矶, children=null 
SingleTreeNode id=1, pId=0, name=中国, SingleTreeNode id=6, pId=0, name=美国, SingleTreeNode id=2, pId=1, name=湖南, SingleTreeNode id=3, pId=2, name=长沙, SingleTreeNode id=4, pId=1, name=湖北, SingleTreeNode id=5, pId=4, name=武汉, SingleTreeNode id=7, pId=6, name=加利福尼亚, SingleTreeNode id=8, pId=7, name=洛杉矶