（已解决）按照老师讲的，我的出现下边错误是什么原因呢，求帮助
信息: Server startup in 2652 ms
123
十二月 31, 2016 3:17:31 下午 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet [search] in context with path [/ajaxtest] threw exception [Servlet execution threw an exception] with root cause
java.lang.ClassNotFoundException: net.sf.json.JSONArray
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1891)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1734)
at com.imooc.SearchServlet.doGet(SearchServlet.java:37)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:218)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:442)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1082)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:623)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2517)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2506)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
package com.imooc;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import net.sf.json.JSONArray;
public class SearchServlet extends HttpServlet {
//这些是模拟数据
static List<String> datas = new ArrayList<String>();
static {
datas.add("ajax");
datas.add("ajaxpost");
datas.add("becky");
datas.add("bill");
datas.add("james");
datas.add("jerry");
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
System.out.println("123");
//首先获得客户端发送来的数据keyword
String keyword = request.getParameter("keyword");
//获得关键字后进行处理，得到关联数据
List<String> listData = getData(keyword);
//返回json格式
System.out.println(JSONArray.fromObject(listData));
// response.getWriter().write(JSONArray.fromObject(listData).toString());
}
//获得关联数据的方法
public List<String> getData(String keyword){
List<String> list = new ArrayList<String>();
for (String data:datas){
if (data.contains(keyword)){
list.add(data);
}
}
return list;
}
}<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<style type="text/css">
#mydiv{
position:absolute;
left:50%;
top:50%;
margin-left:-200px;
margin-top:-50;
}
</style>
<script type="text/javascript">
var xmlHttp;
//获得用户输入内容 的关联信息 的函数
function getMoreContents(){
//首先要获得用户输入的内容
var content = document.getElementById("keyword");
if (content.value == ""){
return;
}
//然后要给服务器发送用户输入的内容，因为我们采用的是ajax异步发送数据；
//所以我们要使用一个对象,叫做XmlHttp对象
xmlHttp = createXMLHttp();//获得xmlHttp对象
//要给服务器发送数据
var url = "search?keyword="+escape(content.val);
//true表示javascript脚本会在send方法之后继续执行，而不会等待来自服务器的响应
xmlHttp.open("GET", url, true);
//xmlHttp绑定回调方法，这个回调方法会在xmlHttp状态改变的时候被调用
//xmlhttp的转态为0-4，我们只关心4（compete）这个状态
//所以说，当完成之后再调用回调方法才有意义。
xmlHttp.onreadystatechange = callback;
xmlHttp.send(null);
}
//获得XMLHttp对象
function createXMLHttp(){
//对于大多数浏览器都使用
var xmlHttp;
if (window.XMLHttpRequest){
xmlHttp = new XMLHttpRequest();
}
//要考虑浏览器的兼容性
if (window.ActiveXObject){
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
if (!xmlHttp){
xmlHttp = new ActiveXObject("Msxml.XMLHTTP");
}
}
return xmlHttp;
}
//回调函数
function callback(){
//4代表完成
if (xmlHttp.readyState == 4){
//200代表服务器响应成功
//404代表资源未找到，500代表服务器内部错误
if (xmlHttp.status == 200){
//交互成功，获得相应的响应数据，是文本格式
var result = xmlHttp.responseText;
//解析获得数据
var json = eval("("+result+")");
//获得数据后就可以动态的显示这些数据了，把这些数据展示到输入框的下面
alert(json);
}
}
}
//设置关联数据的展示，参数代表的是服务器传递过来的关联数据
function setContent(contents){
//首先获取关联数据的长度，以此来确定生成多少<tr></tr>
var size = contens.length;
//设置内容
for(var i = 0;i < size; i++){
var nextNode = content[i];//代表的是json格式数据的第i个元素
var tr = document.createElement("tr");
var td = document.createElement("td");
td.setAttribute("border", "0");
td.setAttribute("bg_color", "#FFAFA");
td.onmouseover = function() {
this.className = 'mouseOver';
};
td.onmouseout = function() {
this.className = 'mouseOut';
};
td.onclick = function() {
//这个方法实现的是：当用鼠标点击一个关联的数据时，所点击关联数据自动设置为输入框数据
};
var text = document.createTextNode(nextNode);
td.appendChild(text);
tr.appendChild(td);
document.getElementById("content_table_body").appendChild(tr);
}
}
</script>
</head>
<body>
<div id="mydiv">
<!-- 输入框 -->
<input type="text" size="60" id="keyword" onkeyup="getMoreContents()"/>
<input type="button" value="百度一下 " width="50px">
<!-- 下面是内容展示区域 -->
<div id="popDiv">
<table id="content_table" bgcolor="#FFFAFA" border="0" cellspacing="0" cellpading="0">
<tbody id="content_table_body">
<!-- 动态查询出来的数据显示在这个地方 -->
<tr><td>ajax</td></tr>
<tr><td>ajax1</td></tr>
<tr><td>ajax2</td></tr>
</tbody>
</table>
</div>
</div>
</body>
</html><?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>ajaxtest</display-name> <welcome-file-list> <welcome-file>index.html</welcome-file> <welcome-file>index.htm</welcome-file> <welcome-file>index.jsp</welcome-file> <welcome-file>default.html</welcome-file> <welcome-file>default.htm</welcome-file> <welcome-file>default.jsp</welcome-file> </welcome-file-list> <servlet> <servlet-name>search</servlet-name> <servlet-class>com.imooc.SearchServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>search</servlet-name> <url-pattern>/search</url-pattern> </servlet-mapping> </web-app>
