本來要做一個文件目錄瀏覽界面,需要遍歷所有的文件和目錄,很顯然一次性讀取時很費時費力的一件事情。
因此就需要做異步加載....
準備工作:
1下載 JQuery ZTree
復制其中的JS和CSS即可,其實沒必要引那么多,用什么引什么就可以。

2 需要fastJSON,用來轉換JSON對象
我下載JAR包后,引入到Eclipse中總是報找不到class錯誤。
解決辦法:把jar包放在WEB-INF/lib下即可。
代碼實例:
index.jsp
<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><title>Insert title here</title> <link rel="stylesheet" href="resources/css/demo.css" type="text/css"> <link rel="stylesheet" href="resources/css/zTreeStyle/zTreeStyle.css" type="text/css"> <script type="text/javascript" src="resources/js/jquery-1.4.4.min.js"></script> <script type="text/javascript" src="resources/js/jquery.ztree.core-3.5.js"></script> </head><body> <div class="zTreeDemoBackground left">  <ul id="treeDemo" class="ztree"></ul> </div> <SCRIPT type="text/javascript">  var setting = {     data: {      simpleData: {       enable: true      }     } ,    async: {     enable: true,     url:"/TestZTree/test",     autoParam:["id", "name", "level"],     otherParam:{"otherParam":"zTreeAsyncTest"},     dataFilter: filter    }  };   function filter(treeId, parentNode, childNodes) {   if (!childNodes) return null;   for (var i=0, l=childNodes.length; i<l; i++) {    childNodes[i].name = childNodes[i].name.replace(//.n/g, '.');   }   return childNodes;  }  var zNodes =[    { id:1, pId:0, name:"parentNode 1", open:true},    { id:11, pId:1, name:"parentNode 11",isParent:true},    { id:111, pId:11, name:"leafNode 111"},    { id:112, pId:11, name:"leafNode 112"},    { id:12, pId:1, name:"parentNode 12",isParent:true},    { id:121, pId:12, name:"leafNode 121"},    { id:13, pId:1, name:"parentNode 13", isParent:true},    { id:2, pId:0, name:"parentNode 2", isParent:true}   ];    $(document).ready(function(){    $.fn.zTree.init($("#treeDemo"), setting, zNodes);   });  </SCRIPT></body></html>testServlet.java
package com.test;import java.io.IOException;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.alibaba.fastjson.JSON;import com.alibaba.fastjson.JSONArray;import com.alibaba.fastjson.JSONObject;public class testServlet extends HttpServlet{ @Override  public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {   doPost(request, response);  }   @Override  public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {   String id = request.getParameter("id");   String name = request.getParameter("name");   String level = request.getParameter("level");   String otherParam = request.getParameter("otherParam");   System.out.println(id + "|" + name + "|" + level + "|" + otherParam);      List<HashMap<String,Object>> list = new ArrayList<HashMap<String,Object>>();   for(int i = 0; i < 5; i++){    HashMap<String,Object> hm = new HashMap<String,Object>(); //最外層,父節點       hm.put("id",id+i);//id屬性 ,數據傳遞    hm.put("name", id+i); //name屬性,顯示節點名稱    hm.put("pId", id);        list.add(hm);   }   response.getWriter().write(JSON.toJSONString(list));  } }web.xml
<?xml version="1.0" encoding="UTF-8"?><web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <display-name></display-name> <servlet> <servlet-name>testServlet</servlet-name> <servlet-class>com.test.testServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>testServlet</servlet-name> <url-pattern>/test</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list></web-app>
效果圖:

更多關于ztree控件的內容,請參考專題《jQuery插件ztree使用匯總》
以上就是關于jquery異步加載,希望對大家學習jquery程序設計有所幫助。
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