1．该树的特点：
1）无限级树结构
理论上树的深度可以无限，树的深度由xml文件所给的信息确定；
数据加载采用一次加载和动态加载相结合的方法；
每次打开相关页时重新加载树结构，真正的做到了建立树的动态性。
2）复用性
由于这棵树是通过读取xml文件建立的，树的程序代码固定，所以具有很强的复用性。只需要给出xml文件，程序就可以建立对应的树。
3）与用户的交互
由于该程序是用java小程序实现的，所以可以利用java语言中监听事件的类，以响应用户操作。与用户具有更好的交互性。
2．程序结构
这棵树主要有三个类实现：
1） 类treenode：该类起辅助作用，用来描述树的数据结构，并提供一些setter，getter函数用来设置树结构的属性。
2） 类iconrender：该类也是一个辅助类，用来设置树节点的图标。并且可以根据树节点的选中状态改变图标。
3） 类applettree：该类是建立这棵树的主要类，它继承自applet并且实现了treeselectionlistener接口，以用来监听用户操作。树结构由java类jtree显示，我们只需要合理的设定jtree的属性就可以构造出这棵树。而它的属性是通过jdom中的element读取xml文件提供的。上面已经提到监听用户操作是通过实现treeselectionlistener接口完成的，但是只监听不响应毫无用处。怎样才能将监听到的用户操作传给相应的类以响应用户的操作呢？这里用的方法是通过url将参数传递给jsp文件，再由jsp文件传给相应的操作类实现的。
这三个类的代码如下：
1．treenode类
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;
}
}
2. iconrender类
import javax.swing.*;
import java.awt.*;
import javax.swing.tree.*;
import javax.swing.tree.defaulttreecellrenderer;
iconrender
class extends defaulttreecellrenderer {
//创建用于显示的图标
public static final imageicon leafselectedicon = new imageicon("openedfolder.ico");
public static final imageicon leafunselectedicon = new imageicon("closedfolder.ico");
public static final imageicon folderopen = new imageicon("openedfolder.ico");
public static final imageicon folderclose = new imageicon("closedfolder.ico");
//设定图标随选中状态的变化
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();
if((leafselectedicon != null)&&(leafunselectedicon != null))
system.out.println("iconrender:trace");
setleaficon(leafunselectedicon);
setopenicon(folderopen);
setclosedicon(folderclose);
}
}
3．applettree类
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.w3c.dom.nodelist;
import org.jdom.input.*;
import java.io.*;
import java.util.*;
import java.net.*;
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.*;
class mywindowlistener extends windowadapter
{
public void windowclosing(windowevent e)
{
system.exit(1);
}
}
public class applettree extends applet implements treeselectionlistener
{
private jtree tree;
private treepath path;
private jscrollpane treeview;
private defaultmutabletreenode top;
private defaultmutabletreenode clicknode;
private string link;
public applettree(){
}
mouselistener ml = new mouseadapter() {
public void mousepressed(mouseevent e) {
int selrow = tree.getrowforlocation(e.getx(), e.gety());
treepath selpath = tree.getpathforlocation(e.getx(), e.gety());
if(selrow != -1) {
if(e.getclickcount() == 1) {
system.out.print("点击一次鼠标");
//得到最后一个节点
defaultmutabletreenode treenode = (defaultmutabletreenode)selpath.getlastpathcomponent();
boolean isleaf = treenode.isleaf();
treenode objtreenode = (treenode)treenode.getuserobject();
system.out.println(isleaf);
system.out.println(objtreenode .getname()) ;
system.out.println(objtreenode .getid()) ;
if(isleaf)
{//如果为叶子节点就传出去进行查询操作
try
{
getappletcontext().showdocument(new url("http://127.0.0.1:8080/tree/showdevice.htm"),"f2" );
}
catch(exception ex)
{
system.out.print(ex);
}
}
}
else if(e.getclickcount() == 2) {
system.out.print("点击两次鼠标");
//getappletcontext().showdocument(new url("http://www.csdn.net/"));
//mydoubleclick(selrow, selpath);
}
}
}
};
public void start()
{
super.start();
}
public void init(){
try{
super.init();
this.setlayout(new gridlayout(1,1));
tree=createtree(new fileinputstream("e:/example/treexml.xml"));
tree.getselectionmodel().setselectionmode(treeselectionmodel.single_tree_selection);
tree.putclientproperty("jtree.linestyle","angled");
tree.setshowsroothandles(true);
tree.seteditable(true);
tree.addtreeselectionlistener( this );
iconrender render=new iconrender();
tree.setcellrenderer(render);
treeview = new jscrollpane(tree);
//toppanel.add(tree);
this.add(treeview);
tree.addmouselistener(ml);
}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("havechildren"));
top=new defaultmutabletreenode(rootnode);
addnode(root,top);
} catch (exception ex) {
ex.printstacktrace();
}
//可以在这里改变jtree中连线的颜色
uimanager.put( "tree.hash", new coloruiresource(color.red) );
return new jtree(top);
}
/**
*
* @param e 待加入树中的jdom元素
* @param fathernode 树节点父亲节点
*/
private void addnode(element e,defaultmutabletreenode fathernode){
try{
iterator it=e.getchildren().iterator();
if(!it.hasnext())
return;
while(it.hasnext()){
element sub=(element)it.next();
string id=new string(sub.getattributevalue("id").getbytes(),"gb2312");
string name=new string(sub.getattributevalue("name").getbytes(),"gb2312");
string link=new string(sub.getattributevalue("havechildren").getbytes(),"gb2312");
system.out.println(id);
system.out.println(name);
system.out.println(link);
treenode tempnode=new treenode(id,name,link);
defaultmutabletreenode node=new defaultmutabletreenode(tempnode);
fathernode.add(node);
if(link.equals("true")){
system.out.println("true~! equal test");
addnode(sub,node);
}
}
}
catch(exception exp)
{
system.out.println("encoding fail");
}
}
/**
* 根据id,查找树节点,//广度优先
* @param id 节点id
* @param rootnode 树根节点
* @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();
}
}
}
public static void main(string[] args ){
jframe frame1=new jframe("test");
applettree tree=new applettree();
tree.init();
frame1.getcontentpane().add(tree);
frame1.setsize(600,600);
frame1.show();
frame1.addwindowlistener(new mywindowlistener());
}
}
文章整理：西部数码--专业提供域名注册、虚拟主机服务
http://www.west263.com
以上信息与文章正文是不可分割的一部分,如果您要转载本文章,请保留以上信息，谢谢!
