用Java实现文本形式的树状结构显示

代码如下，可根据需求衍生出各种格式的输出和使用。

package test;import java.util.ArrayList;import java.util.List;public class Folder ...{public Folder(String title) ...{this.title = title;}private String title;private List children = new ArrayList();public void addChild(Folder f) ...{children.add(f);}public List getChildren() ...{return children;}public void setChildren(List children) ...{this.children = children;}public String getTitle() ...{return title;}public void setTitle(String title) ...{this.title = title;}public String toString(String lftStr, String append) ...{StringBuilder b = new StringBuilder();b.append(append + title);b.append("\n");if (children.size() > 0) ...{for (int i = 0; i < children.size() - 1; i++) ...{b.append(lftStr+children.get(i).toString(lftStr + "│", "├"));}b.append(lftStr + children.get(children.size() - 1).toString(lftStr + " ", "└"));}return b.toString();}public static void main(String[] args) ...{Folder root = new Folder("菜单列表");Folder f1 = new Folder("开始菜单");root.addChild(f1);Folder f1_1 = new Folder("程序");f1.addChild(f1_1);Folder f1_1_1 = new Folder("附件");f1_1.addChild(f1_1_1);Folder f1_1_1_1 = new Folder("娱乐");f1_1_1.addChild(f1_1_1_1);Folder f1_1_1_2 = new Folder("娱乐2");f1_1_1.addChild(f1_1_1_2);Folder f1_2 = new Folder("辅助工具");f1.addChild(f1_2);Folder f2 = new Folder("My Documents ");root.addChild(f2);Folder f3 = new Folder("My Documents2 ");root.addChild(f3);System.out.println(root.toString(" ", ""));}}


运行结果如下：

菜单列表
├开始菜单
│├程序
││└附件
││ ├娱乐
││ └娱乐2
│└辅助工具
├My Documents
└My Documents2

应网友要求，增加了JDK 1.4版及以下的程序版本，取消了泛型。

import java.util.ArrayList;
import java.util.List;
public class Folder{
public Folder(String title)
{
this.title = title;
}
private String title;
private List children = new ArrayList();
public void addChild(Folder f)
{
children.add(f);
}
public List getChildren()
{
return children;
}
public void setChildren(List children)
{
this.children = children;
}
public String getTitle()
{
return title;
}
public void setTitle(String title)
{
this.title = title;
}
public String toString(String lftStr, String append)
{
StringBuilder b = new StringBuilder();
b.append(append + title);b.append(" ");
if (children.size() > 0)
{
for (int i = 0; i < children.size() - 1; i++)
{
b.append(lftStr + ((Folder) children.get(i)).toString(lftStr + "│", "├"));
}
b.append(lftStr + ((Folder) children.get(children.size() - 1)).toString(lftStr + " ", "└"));
}
return b.toString();
}
public static void main(String[] args)
{
Folder root = new Folder("菜单列表");
Folder f1 = new Folder("开始菜单");
root.addChild(f1);Folder f1_1 = new Folder("程序");
f1.addChild(f1_1);Folder f1_1_1 = new Folder("附件");
f1_1.addChild(f1_1_1);Folder f1_1_1_1 = new Folder("娱乐");
f1_1_1.addChild(f1_1_1_1);Folder f1_1_1_2 = new Folder("娱乐2");
f1_1_1.addChild(f1_1_1_2);Folder f1_2 = new Folder("辅助工具");
f1.addChild(f1_2);Folder f2 = new Folder("My Documents ");
root.addChild(f2);Folder f3 = new Folder("My Documents2 ");
root.addChild(f3);System.out.println(root.toString(" ", ""));
}
}