JTree是做什么用的？

Question

http://java.sun.com/products/jfc/tsc/articles/treetable1/index.html

Answer 1

JTree, javax.swing.JTree
JTree是java SWING中最复杂的组件之一，它最平常的应用大概是以文件夹和树页图来显示
分层的数据，比如做个类似WINDOWS资源管理器的东东
帖篇我写的一个有关树的类，只是个类，需要加JFRAME之类的东西哦，这个类就有点象资源管理器，界面图标用的是LINUX的KDE
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.io.*;
import javax.swing.tree.*;
import javax.swing.border.*;
import java.applet.*;
public class TreeDemoX extends JPanel
{
private JSplitPane split=null;
private JPanel northpanel=null;
private JPanel southpanel=null;
private JTree tree=null;
private JScrollPane treescroll=null;
JScrollPane viewscroll=null;
AudioClip treechange,treeexpand;
private ViewPanel viewpanel=null;
public TreeDemoX()
{
setLayout(new BorderLayout());
treechange=Applet.newAudioClip(getClass().getResource("sound\\opendir.wav"));
treeexpand=Applet.newAudioClip(getClass().getResource("sound\\treeexpand.wav"));
treeInit();
viewpanel=new ViewPanel();
viewpanel.viewload(new File("c:\\"),tree.getPathForRow(0),tree);
treescroll=new JScrollPane(tree);
viewscroll=new JScrollPane(viewpanel);
viewpanel.sss=viewscroll;
splitInit();
add(split,BorderLayout.CENTER);
}
public void treeInit()
{
tree=new JTree(createTreeModel());
tree.putClientProperty("JTree.lineStyle","Angled");
tree.setCellRenderer(new TreeRenderer());
tree.addTreeExpansionListener(
new TreeExpansionListener()
{
public void treeCollapsed(TreeExpansionEvent e)
{
treeexpand.play();
}
public void treeExpanded(TreeExpansionEvent e)
{
TreePath path=e.getPath();
treeNode node=(treeNode)path.getLastPathComponent();
if(!node.isex())
{
DefaultTreeModel model=(DefaultTreeModel)tree.getModel();
node.explore();
model.nodeStructureChanged(node);
}
treeexpand.play();
}
});
tree.addTreeSelectionListener(
new TreeSelectionListener()
{
public void valueChanged(TreeSelectionEvent e)
{
TreePath path=e.getPath();
treeNode node=(treeNode)path.getLastPathComponent();
viewpanel.viewload((File)(node.getUserObject()),new TreePath(node.getPath()),tree);
treechange.play();
viewscroll.validate();
}
});
}
public DefaultTreeModel createTreeModel()
{
File root=new File("C:\\");
treeNode rootNode=new treeNode(root);
rootNode.explore();
return new DefaultTreeModel(rootNode);
}
public void splitInit()
{
if(treescroll!=null && viewpanel!=null)
{
split=new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,treescroll,viewscroll);
split.setContinuousLayout(true);
split.setOneTouchExpandable(true);
split.setDividerLocation(200);
}
}
//////////////////////////////////////////////TreeRenderer
class  TreeRenderer extends DefaultTreeCellRenderer
{
ImageIcon open,close,root;
public TreeRenderer()
{
open=new ImageIcon(getClass().getResource("image\\tree\\new\\diropen.gif"));
close=new ImageIcon(getClass().getResource("image\\tree\\new\\dirclose.gif"));
root=new ImageIcon(getClass().getResource("image\\tree\\new\\root.gif"));
}
public Component getTreeCellRendererComponent(JTree tree,
Object vue,boolean selected,boolean expanded,boolean leaf,int row,boolean hasFocus)
{
JLabel label=(JLabel)(super.getTreeCellRendererComponent(tree,vue,selected,expanded,leaf,row,hasFocus));
if(row==0)
setIcon(root);
if(!leaf && row!=0)
{
if(hasFocus)
setIcon(open);
else
setIcon(close);
}
return label;
}
}//////////////////////////////////////////////////TreeRenderer
}
//////////////////////
//      treeModel       //
/////////////////////
class treeNode extends DefaultMutableTreeNode
{
boolean ex=false;
public treeNode(File f)
{
setUserObject(f);
}
public boolean isDirectory()
{
return ((File)getUserObject()).isDirectory();
}
public boolean isex()
{
return ex;
}
public File getFile()
{
return (File)getUserObject();
}
public boolean getAllowsChildren()
{
return isDirectory();
}
public boolean isLeaf()
{
return !isDirectory();
}
public String toString()
{
File file=getFile();
String filename=file.toString();
int index=filename.lastIndexOf("\\");
if(index!=-1 && index!=filename.length()-1)
return filename.substring(index+1);
else 
return filename;
}
public void explore()
{
if(!isex() && isDirectory())
{
File[] files=getFile().listFiles();
for(int i=0;i<files.length;i++)
{
if(files[i].isDirectory())
add(new treeNode(files[i]));
}
ex=true;
}
}
}
//***************************TreeNode/////////////////////////////////
//             ViewPanel                      //
////////////////////////////////
class ViewPanel extends JPanel
{
ImageIcon icof,icod;
File[] f,d;
JScrollPane sss;
AudioClip enterfile,opendir;
ImageIcon zip,def,dir,doc,exe,fon,gif,htm,jpg,bmp,log,eml,music,pdf,scr,txt,vedio,wav,
bat,dll,dat,javaf,sys,classf,asf,inf,png;
public ViewPanel()
{
//setLayout(new FlowLayout());
setBackground(Color.white);
        icof=new ImageIcon(getClass().getResource("image\\f.gif"));
icod=new ImageIcon(getClass().getResource("image\\tree\\new\\dirclose.gif"));
enterfile=Applet.newAudioClip(getClass().getResource("sound\\enterfile.wav"));
opendir=Applet.newAudioClip(getClass().getResource("sound\\opendir.wav"));
zip=new ImageIcon(getClass().getResource("image\\tree\\new\\zip.gif"));
def=new ImageIcon(getClass().getResource("image\\tree\\new\\default.gif"));

doc=new ImageIcon(getClass().getResource("image\\tree\\new\\doc.gif"));
exe=new ImageIcon(getClass().getResource("image\\tree\\new\\exe.gif"));
fon=new ImageIcon(getClass().getResource("image\\tree\\new\\fon.gif"));
gif=new ImageIcon(getClass().getResource("image\\tree\\new\\gif.gif"));
htm=new ImageIcon(getClass().getResource("image\\tree\\new\\htm.gif"));
jpg=new ImageIcon(getClass().getResource("image\\tree\\new\\jpg.gif"));
bmp=new ImageIcon(getClass().getResource("image\\tree\\new\\bmp.gif"));
log=new ImageIcon(getClass().getResource("image\\tree\\new\\log.gif"));
eml=new ImageIcon(getClass().getResource("image\\tree\\new\\eml.gif"));
music=new ImageIcon(getClass().getResource("image\\tree\\new\\music.gif"));
pdf=new ImageIcon(getClass().getResource("image\\tree\\new\\pdf.gif"));
scr=new ImageIcon(getClass().getResource("image\\tree\\new\\scr.gif"));
txt=new ImageIcon(getClass().getResource("image\\tree\\new\\txt.gif"));
vedio=new ImageIcon(getClass().getResource("image\\tree\\new\\video.gif"));
wav=new ImageIcon(getClass().getResource("image\\tree\\new\\wav.gif"));
bat=new ImageIcon(getClass().getResource("image\\tree\\new\\bat.gif"));
dll=new ImageIcon(getClass().getResource("image\\tree\\new\\dll.gif"));
dat=new ImageIcon(getClass().getResource("image\\tree\\new\\dat.gif"));
javaf=new ImageIcon(getClass().getResource("image\\tree\\new\\java.gif"));
sys=new ImageIcon(getClass().getResource("image\\tree\\new\\sys.gif"));
classf=new ImageIcon(getClass().getResource("image\\tree\\new\\class.gif"));
asf=new ImageIcon(getClass().getResource("image\\tree\\new\\asf.gif"));
inf=new ImageIcon(getClass().getResource("image\\tree\\new\\inf.gif"));
png=new ImageIcon(getClass().getResource("image\\tree\\new\\png.gif"));
}
public void viewload(File fff,TreePath ttt,JTree jtree)
{
removeAll();
File c=fff;
        File[] files=c.listFiles();
int i=0,j=0;
for(int k=0;k<files.length;k++)
{
if(files[k].isFile())
i++;
else if(files[k].isDirectory())
j++;
}
f=new File[i];
d=new File[j];
i=0;j=0;
for(int k=0;k<files.length;k++)
{
if(files[k].isFile())
{
 f[i]=files[k];
 i++;
}
else if(files[k].isDirectory())
{
d[j]=files[k];
j++;
}
}
setLayout(new GridLayout((int)(files.length/6)+1,6));
for(int a=0;a<j;a++)
add(new FileIcon(d[a],ttt,jtree,a));
for(int b=0;b<i;b++)
add(new FileIcon(f[b],ttt,jtree,b));
}
/*
public void reviewload(File fff)
{
viewload(fff); }
*/
//*********************FileIcon
class FileIcon extends JLabel
{
public FileIcon(final File str,final TreePath path,final JTree jtree,final int i)
{
super(str.getName());
setToolTipText(str.getName());
setFont(new Font("黑体",Font.PLAIN,12));
setForeground(Color.gray);
setHorizontalTextPosition(SwingConstants.CENTER);
setVerticalTextPosition(SwingConstants.BOTTOM);
setHorizontalAlignment(SwingConstants.CENTER);
//setVerticalAlignment(SwingConstants.BOTTOM);
setPreferredSize(new Dimension(40,70));
if(str.isDirectory())
{
setIcon(icod);
addMouseListener(
new MouseListener()
{
public void mouseEntered(MouseEvent e)
{
FileIcon.this.setBorder(new TitledBorder("Directory"));
((TitledBorder)(FileIcon.this.getBorder())).setTitleColor(Color.blue);
FileIcon.this.repaint();
enterfile.play();
}
public void mouseExited(MouseEvent e)
{
FileIcon.this.setBorder(null);
FileIcon.this.repaint();
}
public void mousePressed(MouseEvent e)
{
}
public void mouseReleased(MouseEvent e)
{
}
public void mouseClicked(MouseEvent e)
{
if(e.getClickCount()==2)
{
ViewPanel.this.viewload(str,path,jtree);
opendir.play();
jtree.expandPath(path);
treeNode n=(treeNode)(path.getLastPathComponent());
treeNode n2=(treeNode)(n.getChildAt(i));
jtree.setSelectionPath(new TreePath(n2.getPath()));
//jtree.repaint();
//jtree.validate();
if(sss!=null)
sss.validate();
}
}
});
}
else
{
String name=getPostfix(str.getName());
//System.out.println(name);
if(name.equals("zip") || name.equals("rar"))
setIcon(zip);
else if(name.equals("doc"))
setIcon(doc);
else if(name.equals("exe"))
setIcon(exe);
else if(name.equals("ttf") || name.equals("fon"))
setIcon(fon);
else if(name.equals("gif"))
{
setIcon(gif);
}
else if(name.equals("htm") || name.equals("html"))
{
setIcon(htm);
}
else if(name.equals("jpg"))
setIcon(jpg);
else if(name.equals("bmp"))
setIcon(bmp);
else if(name.equals("log"))
setIcon(log);
else if(name.equals("eml"))
setIcon(eml);
else if(name.equals("mid") || name.equals("mp3"))
setIcon(music);
else if(name.equals("pdf"))
setIcon(pdf);
else if(name.equals("scr"))
setIcon(scr);
else if(name.equals("txt"))
setIcon(txt);
else if(name.equals("rm") || name.equals("avi"))
setIcon(vedio);
else if(name.equals("wav"))
setIcon(wav);
else if(name.equals("bat"))
setIcon(bat);
else if(name.equals("dll"))
setIcon(dll);
else if(name.equals("dat"))
setIcon(dat);
else if(name.equals("java"))
setIcon(javaf);
else if(name.equals("sys"))
setIcon(sys);
else if(name.equals("class"))
setIcon(classf);
else if(name.equals("asf"))
setIcon(asf);
else if(name.equals("inf"))
setIcon(inf);
else if(name.equals("png"))
setIcon(png);
else
setIcon(def);
addMouseListener(
new MouseListener()
{
public void mouseEntered(MouseEvent e)
{
FileIcon.this.setBorder(new TitledBorder("File"));
((TitledBorder)(FileIcon.this.getBorder())).setTitleColor(Color.red);
FileIcon.this.repaint();
enterfile.play();
}
public void mouseExited(MouseEvent e)
{
FileIcon.this.setBorder(null);
FileIcon.this.repaint();
}
public void mousePressed(MouseEvent e)
{
}
public void mouseReleased(MouseEvent e)
{
}
public void mouseClicked(MouseEvent e)
{
}
});
}
}
public String getPostfix(String str)
{
int index=str.lastIndexOf(".");
String s;
if(index!=-1)
{
s=str.substring(index+1);
}
else
{
s="???...";
}
//System.out.println(s);
return s.toLowerCase();
}
}
}

Answer 2

天呀，那么长代码查一下JAVA文档吧