如何设置jtree 图标

import java.awt.*;  

import java.awt.image.BufferedImage;  

import java.io.*;  

import javax.imageio.ImageIO;  

import javax.swing.*;  

import javax.swing.tree.*;  

 

public class TreeIcons  

{  

    BufferedImage[] images;  

 

    public TreeIcons(BufferedImage[] images)  

    {  

        this.images = images;  

    }  

 

    private JPanel getContent()  

    {  

        JPanel panel = new JPanel(new GridLayout(1,0));  

        panel.add(new JScrollPane(getLeftTree()));  

        panel.add(new JScrollPane(getRightTree()));  

        return panel;  

    }  

 

    private JTree getLeftTree()  

    {  

        JTree tree = getTree();  

        DefaultTreeCellRenderer renderer =  

        (DefaultTreeCellRenderer)tree.getCellRenderer();  

        // make changes to renderer for this tree  

        // works okay if the size of the new images does  

        // not exceed the size of the default images  

        renderer.setClosedIcon(new ImageIcon(images[0]));  

        renderer.setOpenIcon(new ImageIcon(images[1]));  

        renderer.setLeafIcon(new ImageIcon(images[2]));  

        return tree;  

    }  

 

    private JTree getRightTree()  

    {  

        JTree tree = getTree();  

        // set a renderer that allows more fine-grained  

        // control of rendering for varying conditions  

        tree.setCellRenderer(new IconRenderer(images));  

        return tree;  

    }  

 

    private JTree getTree()  

    {  

        String[] birds = {  

            // branches  |<-- child leaf nodes -->|  

            "hawks",   "gray",    "red-tailed", "rough-legged",  

            "falcons", "harrier", "kestrel",    "kite",   

            "owls",    "barred",  "saw-whet",   "snowy"  

            };  

        DefaultMutableTreeNode root = new DefaultMutableTreeNode("birds");  

        DefaultMutableTreeNode[] nodes = new DefaultMutableTreeNode[birds.length];  

        for(int j = 0; j < nodes.length; j++)  

            nodes[j] = new DefaultMutableTreeNode(birds[j]);  

        for(int j = 0; j < 9; j += 4)  

        {  

            root.insert(nodes[j], j % 3);  

            for(int k = j + 1; k < j + 4; k++)  

            nodes[j].insert(nodes[k], k - j - 1);  

        }  

        DefaultTreeModel model = new DefaultTreeModel(root);  

        return new JTree(model);  

    }     

 

    public static void main(String[] args) throws IOException  

    {  

        String[] ids = { "closed16", "open16", "leaf16" };  

        BufferedImage[] bis = new BufferedImage[ids.length];  

        for(int j = 0; j < bis.length; j++)  

        bis[j] = ImageIO.read(new File("images/" + ids[j] + ".gif"));  

        // to make uniform changes for all JTrees in this app  

        //UIManager.put("Tree.closedIcon", new ImageIcon(bis[0]));  

        //UIManager.put("Tree.openIcon",   new ImageIcon(bis[1]));  

        //UIManager.put("Tree.leafIcon",   new ImageIcon(bis[2]));  

        JFrame f = new JFrame();  

        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  

        f.setContentPane(new TreeIcons(bis).getContent());  

        f.setSize(500,400);  

        f.setLocation(200,200);  

        f.setVisible(true);  

    }  

}  

 

class IconRenderer extends DefaultTreeCellRenderer  

{  

    ImageIcon closedIcon;  

    ImageIcon openIcon;  

    ImageIcon leafIcon;  

 

    public IconRenderer(BufferedImage[] images)  

    {  

        closedIcon = new ImageIcon(images[0]);  

        openIcon   = new ImageIcon(images[1]);  

        leafIcon   = new ImageIcon(images[2]);  

    }  

 

    public Component getTreeCellRendererComponent(JTree tree,  

                                                    Object value,  

                                                    boolean sel,  

                                                    boolean expanded,  

                                                    boolean leaf,  

                                                    int row,  

                                                    boolean hasFocus)  

    {  

        // start with default behavior  

        super.getTreeCellRendererComponent(tree, value, sel, expanded,   

        leaf, row, hasFocus);  

 

        // customize based on local conditions/state  

        DefaultMutableTreeNode node = (DefaultMutableTreeNode)value;  

        String userObject = (String)node.getUserObject();  

        boolean isOwl = userObject.equalsIgnoreCase("owls");  

        if(isOwl)  

            setIcon(closedIcon);  

        else if(leaf)  

            setIcon(leafIcon);  

        else if(expanded)  

            setIcon(openIcon);  

        return this;  

    }  

}