求助 JAVA AJAX

jsp代码
<%@ 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">
<script type="text/javascript" src="${pageContext.request.contextPath}/util.js"></script>
<title>ajax学习</title>
<script>
window.onload=function(){
document.getElementById("btn1").onclick=function(){
//发出已补请求
//1/得到xhr对象
var xhr=getXHR();
//2.注册状态变化监听器
xhr.onreadystatechange=function(){
if(xhr.readyState==4)
{
if(xhr.status==200)
{
alert("服务器响应了");
document.getElementById("mytext").innerHTML=xhr.responseText;
}
}
}
//3.建立与服务器的连接
xhr.open("GET","AjaxServlet"+"?time="+new Date().getTime());
//4.向服务器发出请求
xhr.send();
}
}
</script>
</head>
<body>
<button id="btn1">点我呀</button>
<div id="mytext"></div>
</body>
</html>java端package com.levi.servletajax;import java.io.IOException;
import java.io.PrintWriter;import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;/**
 * Servlet implementation class AjaxServlet
 */
public class AjaxServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public AjaxServlet() {
        super();
        // TODO Auto-generated constructor stub
    } /**
 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
 */
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
} /**
 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
 */
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setCharacterEncoding("utf-8");
System.out.println("ajax后台交互成功");
PrintWriter write=response.getWriter();
write.println("我是输出的文字<br>");
write.println("姓名:花2不谢<br/>年龄:20");
write.flush();
}}web.xml文件<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
id="WebApp_ID" version="3.1">
<display-name>WXdemo</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>"AjaxServlet"</servlet-name>
<servlet-class>"com.levi.servletajax.AjaxServlet"</servlet-class>
</servlet> <servlet-mapping>
<servlet-name>AjaxServlet</servlet-name>
<url-pattern>/AjaxServlet</url-pattern>
</servlet-mapping>
</web-app>
错误信息
严重: Allocate exception for servlet [AjaxServlet]
java.lang.ClassNotFoundException: "com.levi.servletajax.AjaxServlet"
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1275)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1109)
at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:508)
at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:489)
at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:119)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1050)
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:779)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:133)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:475)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:498)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:796)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1368)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
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:748)求个具体点的解决方案...

解决方案 »

  1.   

    是不是将web.xml中servlet-class的双引号去掉
      

  2.   

    web.xml里面servlet的name和class去掉双引号
      

  3.   

    <servlet>
            <servlet-name>"AjaxServlet"</servlet-name>
            <servlet-class>"com.levi.servletajax.AjaxServlet"</servlet-class>
        </servlet>
    不用双引号
      

  4.   


    <servlet>
            <servlet-name>AjaxServlet</servlet-name>
            <servlet-class>com.levi.servletajax.AjaxServlet</servlet-class>
        </servlet>这样子的
      

  5.   

        <servlet>
            <servlet-name>"AjaxServlet"</servlet-name>
            <servlet-class>"com.levi.servletajax.AjaxServlet"</servlet-class>
        </servlet>
    不用双引号