java编程两种树形菜单结构的转换代码

首先看看两种树形菜单结构的代码示例。

singletreenode：

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 + "]";
	}
}

这种结构很适合存储到关系型数据库中。

multitreenode：

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 + "]";
	}
}

两种转换器

tomultitreetransformer：

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);
			}
		}
	}
}

tosingletreetransformer：

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);
					}
				}
			}
		}
	}
}

测试

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);
	}
}

输出结果：

[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]] 

总结

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