關鍵詞:xml,jdom,applet,jtree
在我們工作中，常常會碰到樹形組件的生成問題，如果你在開發web application,純粹使用
javascript來生成樹形組件是非常繁瑣的，而且交互性也不不太好。所以許多產品使applet來實現樹形組件的功能。比如說，weblogic,jboss等產品的console.所以，把樹形數據組織成xml文件，用jdom剖析它，最後生成applet就非常有通用的意義。下面，我就給出一個例子，拋磚引玉。
1.準備一個存有屬性數據的xml文件，把它放在classpath中，我這裏是org.xml。
[pre]<?xml version="1.0" encoding="UTF-8"?>
<!--Sample XML file generated by XMLSPY v5 rel. 3 U (http://www.xmlspy.com)-->
<node xmlns="http://www.javabox.com/schemas/org"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.javabox.com/schemas/org
E:/myDemo/org.xsd" name="組織機構" id="-1" desc="" link="#">
<node name="總經理" id="1" desc="" link="#">
<node name="管理副總經理" id="2" desc="" link="#"/>
<node name="生產副總經理" id="3" desc="" link="#">
<node name="項目部" id="7" desc="" link="#"/>
<node name="機械公司" id="8" desc="" link="#"/>
<node name="貝盟公司" id="9" desc="" link="#"/>
<node name="洛斯韋公司" id="9" desc="" link="#"/>
</node>
<node name="總工程師" id="4" desc="" link="#"/>
<node name="總會計師" id="5" desc="" link="#"/>
<node name="總經濟師" id="6" desc="" link="#"/>
</node>
</node>[/pre]
2.確保你可以使用jdom解析器，你如果沒有可以去這裏下載。
3.用於代表樹結點節點的javabean,TreeNode.java
package com.javabox.jtree;
public class TreeNode{
private String id;
private String name;
private String link;
public TreeNode(String id,String name,String link){
this.id=id;
this.name=name;
this.link=link;
}
public String getId(){
return id;
}
public void setId(String Id){
this.id=Id;
}
public void setName(String Name){
this.name=Name;
}
public String getName(){
return name;
}
public String toString(){
return name;
}
public String getLink(){
return link;
}
public void setLink(String link){
this.link=link;
}
}
4.自己寫的TreeCellRenderer,IconRender.java
package com.javabox.jtree;
import javax.swing.*;
import java.awt.*;
import javax.swing.tree.*;
import javax.swing.tree.DefaultTreeCellRenderer;
class IconRender
extends DefaultTreeCellRenderer {
//你需要替換成你的icon
public static final Icon leafSelectedIcon = new ImageIcon("greeball.JPG");
public static final Icon leafUnSelectedIcon = new ImageIcon("greyball.JPG");
public static final Icon folderOpen = new ImageIcon("folderopen.JPG");
public static final Icon folderClose = new ImageIcon("folderclose.JPG");
public Component getTreeCellRendererComponent(JTree tree,
Object value,
boolean selected,
boolean expanded,
boolean leaf,
int row,
boolean hasFocus) {
super.getTreeCellRendererComponent(tree, value, selected, expanded,
leaf, row, hasFocus);
if (leaf && selected) {
setIcon(IconRender.leafSelectedIcon);
}
else if (leaf) {
setIcon(IconRender.leafUnSelectedIcon);
}
return this;
}
public IconRender() {
super();
this.setLeafIcon(leafUnSelectedIcon);
this.setOpenIcon(folderOpen);
this.setClosedIcon(folderClose);
}
}
5.AppletTree.java,該文件解析xml文件，生成含Jtree的applet，你可以把它嵌入到jsp,html文件中使用，也可以直接運行該文件。
package com.javabox.jtree;
import javax.swing.event.*;
import java.awt.*;
import java.applet.*;
import javax.swing.*;
import javax.swing.tree.*;
import java.awt.event.*;
import org.jdom.*;
import org.jdom.input.*;
import java.io.*;
import java.util.*;
import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.plaf.*;
import javax.swing.plaf.basic.*;
import javax.swing.plaf.metal.*;
import java.io.*;
import netscape.javascript.*;
public class AppletTree extends Applet implements TreeSelectionListener
{
private JTree tree;
private TreePath path;
private Panel topPanel;
private DefaultMutableTreeNode top;
private DefaultMutableTreeNode clicknode;
private String link;
public AppletTree(){
}
public void init(){
try{
super.init();
this.setLayout(new GridLayout(1,1));
tree=createTree(new FileInputStream("org.xml"));
tree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
tree.putClientProperty("JTree.lineStyle","Angled");
tree.setShowsRootHandles(true);
tree.setEditable(false);
tree.addTreeSelectionListener( this );
IconRender render=new IconRender();
tree.setCellRenderer(render);
topPanel=new Panel(new BorderLayout());
topPanel.add(tree);
this.add(topPanel);
}catch(Exception e){
e.printStackTrace();
}
}
public JTree createTree(InputStream is){
SAXBuilder builder = new SAXBuilder();
try {
Document doc = builder.build(is);
Element root=doc.getRootElement();
TreeNode rootNode=new
TreeNode(root.getAttributeValue("id"),root.getAttributeValue("name"),root.getAttributeValue("link"));
top=new DefaultMutableTreeNode(rootNode);
addNode(root,top);
} catch (Exception ex) {
ex.printStackTrace();
}
//你可以在這裏改變jtree中連線的顏色，我請教國外的高手才找到的，很酷的哦:)
UIManager.put( "Tree.hash", new ColorUIResource(Color.red) );
return new JTree(top);
}
/**
*
* @param e 待加入樹種的jdom元素
* @param rootNode 樹根節點
*/
private void addNode(Element e,DefaultMutableTreeNode rootNode){
String id=e.getAttributeValue("id");
String name=e.getAttributeValue("name");
String link=e.getAttributeValue("link");
TreeNode node=new TreeNode(id,name,link);
//如有父節點
Element father=e.getParent();
if(father!=null){
String fid=father.getAttributeValue("id");
DefaultMutableTreeNode fatherNode=getTreeNode(fid,rootNode);
if(fatherNode!=null){
fatherNode.add(new DefaultMutableTreeNode(node));
}
}
//如有子節點
Iterator it=e.getChildren().iterator();
while(it.hasNext()){
Element child=(Element)it.next();
addNode(child,rootNode);
}
}
/**
* 根據id,查找樹節點,//廣度優先
* @param id 節點id
* @param rootNode 樹根節點
* @return DefaultMutableTreeNode
*/
private DefaultMutableTreeNode getTreeNode(String id,DefaultMutableTreeNode rootNode){
DefaultMutableTreeNode returnNode=null;
if(rootNode!=null){
Enumeration enum=rootNode.breadthFirstEnumeration();
while(enum.hasMoreElements()){
DefaultMutableTreeNode temp=(DefaultMutableTreeNode)enum.nextElement();
TreeNode node=(TreeNode)temp.getUserObject();
if(node.getId().equals(id)){
returnNode=temp;
break;
}
}
}
return returnNode;
}
public void valueChanged( TreeSelectionEvent event ){
if( event.getSource() == tree ){
path = event.getPath();
clicknode=(DefaultMutableTreeNode)path.getLastPathComponent();
Object uo=clicknode.getUserObject();
if(uo instanceof TreeNode){
TreeNode nd=(TreeNode)clicknode.getUserObject();
link=nd.getLink();
}
//調用一個javascript函數；
// JSObject.getWindow (this).eval ("javascript:window.open('"+link+"')") ;
}
}
public static void main(String[] args ){
JFrame frame=new JFrame("test");
AppletTree tree=new AppletTree();
tree.init();
frame.getContentPane().add(tree);
frame.setSize(600,600);
frame.show();
}
}
6.運行一個這個類，是不是很cool哦，你還可以把它嵌在網頁中，調用javasript函數，達到刷新頁面的目的。
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