java 实现树形结构

package tree;
 
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Font;
import java.awt.Image;
 
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreeSelectionModel;
 
public class treenode extends JFrame implements TreeSelectionListener{
 
    JLabel jl;
    public treenode()
     {
        super("树形结构");
 
        //创建根节点和子节点
        DefaultMutableTreeNode root=new DefaultMutableTreeNode("文本编辑器");
 
        DefaultMutableTreeNode node1=new DefaultMutableTreeNode("文件");
        DefaultMutableTreeNode node2=new DefaultMutableTreeNode("编辑");
 
        //利用根节点创建treemodel
        DefaultTreeModel treemodel=new DefaultTreeModel(root);
        //插入子节点
        treemodel.insertNodeInto(node1, root, root.getChildCount());
        treemodel.insertNodeInto(node2, root, root.getChildCount());
 
        //创建node1的子节点并插入
        DefaultMutableTreeNode leafnode=new DefaultMutableTreeNode("打开");
        treemodel.insertNodeInto(leafnode, node1, node1.getChildCount());
 
        leafnode=new DefaultMutableTreeNode("保存");
        treemodel.insertNodeInto(leafnode, node1, node1.getChildCount());
 
        leafnode=new DefaultMutableTreeNode("另存为");
        treemodel.insertNodeInto(leafnode, node1, node1.getChildCount());
 
        leafnode=new DefaultMutableTreeNode("关闭");
        treemodel.insertNodeInto(leafnode, node1, node1.getChildCount());
 
        //创建node2的子节点并插入
        leafnode=new DefaultMutableTreeNode("剪切");
        treemodel.insertNodeInto(leafnode, node2, node2.getChildCount());
 
        leafnode=new DefaultMutableTreeNode("复制");
        treemodel.insertNodeInto(leafnode, node2, node2.getChildCount());
 
        leafnode=new DefaultMutableTreeNode("粘贴");
        treemodel.insertNodeInto(leafnode, node2, node2.getChildCount());
 
        //创建树对象
        JTree tree =new JTree(treemodel);
 
        tree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
        tree.addTreeSelectionListener(this);
        tree.setRowHeight(20);
 
        //创建节点绘制对象
        DefaultTreeCellRenderer cell=(DefaultTreeCellRenderer)tree.getCellRenderer();
 
        //设置字体
        cell.setFont(new Font("Serif",Font.PLAIN,14));
        cell.setBackgroundNonSelectionColor(Color.white);
        cell.setBackgroundSelectionColor(Color.LIGHT_GRAY);
        cell.setForeground(Color.red);
 
        cell.setIcon(new ImageIcon("/image/folder.jpg"));
 
        //设置选中和不选中时文字的变化颜色
        cell.setTextNonSelectionColor(Color.black);
        cell.setTextNonSelectionColor(Color.black);
 
        this.add(new JScrollPane(tree));
 
         jl=new JLabel("你当前选择的节点为：",JLabel.CENTER);
        jl.setFont(new Font("Serif",Font.PLAIN,14));
        this.add(jl,BorderLayout.SOUTH);
        this.setSize(400, 400);
        this.setVisible(true);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
     }
 
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        treenode t=new treenode();
    }
 
    @Override
    public void valueChanged(TreeSelectionEvent e) {
        // TODO Auto-generated method stub
 
        JTree tree=(JTree)e.getSource();
 
        //获取当前选中的节点
        DefaultMutableTreeNode selectnode=(DefaultMutableTreeNode)tree.getLastSelectedPathComponent();
        String nodename=selectnode.toString();
 
        jl.setText("您当前选择的节点为："+nodename);
 
    }
 
}