var store = Ext.create(‘Ext.data.TreeStore', {
root: {
expanded: true,
children: [
{ text: “留学”, leaf: true },
{ text: “功课”, expanded: true, children: [
{ text: “英语”, leaf: true },
{ text: “代数”, leaf: true}
] },
{ text: “托福”, leaf: true }
]
}
});

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

public class TreeNodeServlet extends HttpServlet {

protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

response.setContentType("text/html;charset=utf-8");

//这里的node是前台的AsyncTreeNode组建中设置的ID，见下面的JS程序

String treeNode = request.getParameter("node");

String json = "";

PrintWriter out = response.getWriter();

if("0".equals(treeNode)) {

json+="[{id:1,text:'0-1'},{id:2,text:'0-2'}]";

}

else if("1".equals(treeNode)) {

json+="[{id:11,text:'0-1-1',leaf:true},{id:12,text:'0-1-2',leaf:true}]";

}

else if("2".equals(treeNode)) {

json+="[{id:21,text:'0-2-1'},{id:22,text:'0-2-2',leaf:true}]";

}

else if("21".equals(treeNode)) {

json+="[{id:211,text:'0-2-1-1',leaf:true},{id:212,text:'0-2-1-2',leaf:true}]";

}

out.write(json);

}

}

Ext.onReady(function(){

var tree = new Ext.tree.TreePanel({

//这里的div-tree是在html中创建的一个对象的id值

el: 'div-tree',

//使用loader方法访问TreeNodeServlet

loader: new Ext.tree.TreeLoader({dataUrl:'../TreeNodeServlet'})

});

var root = new Ext.tree.AsyncTreeNode({id:'0',text:'0'})

tree.setRootNode(root);

tree.render();

root.expand();

});

Ext.onReady(function(){

  var tree1 = new Ext.tree.TreePanel({
    el: 'tree1',
 //这里设置enableDrag为true表示可以从这里拖动元素到别处
    enableDrag:true,
    loader: new Ext.tree.TreeLoader({dataUrl: 'treeData1.txt'})
  });
  var tree2 = new Ext.tree.TreePanel({
    el: 'tree2',
 //这里设置enableDrop为true表示可以在这棵树中放置拖动过来的元素
    enableDrop:true,
    loader: new Ext.tree.TreeLoader({dataUrl: 'treeData2.txt'})
  });
  var root1 = new Ext.tree.AsyncTreeNode({text:'跟节点'});
  var root2 = new Ext.tree.AsyncTreeNode({text:'图书'});
  tree1.setRootNode(root1);
  tree2.setRootNode(root2);
  tree1.render();
  tree2.render();

});

<div id="tree1"></div>
<div id="tree2"></div>

[
    {text:'非叶子结点'},
    {text:'叶子结点',leaf:true}
]
treeData2.txt:

[
  {text:'计算机',children:[
    {text:'Java',children:[
      {text:'Java核心技术',leaf:true},
      {text:'Thinking in Java',leaf:true}
    ]},
    {text:'算法导论',leaf:true}
  ]},
  {text:'音乐',children:[
    {text:'乐理基础',leaf:true},
    {text:'卡尔卡西古典吉他教程',leaf:true}
    ]}
]