javascript-ajax-json-java-servlet互相传值取值的学习心得

来源：互联网发布：3k引擎源码编辑：程序博客网时间：2024/06/01 13:40

前几天突然想学习以下jquery easyui 但是里面涉及到了json的知识，于是恶补起来ajax知识，经过以上的查资料，终于弄清楚javascript-ajax-json-java-servlet互相传值取值,的过程，特此分享出来，希望能帮助到初学的朋友么，也为了日后自己查询是使用，好了闲话少说，看下面代码go！！

使用tomcat6.0

index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">        <title>My JSP 'index.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0">    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--><script type="text/javascript" src="jquery-easyui-1.2.3/json.js"></script><script type="text/javascript">//创建XMLHttpRequeset对象，这个对象是ajax的核心对象function createXMLHttp(){var xmlhttp;   try{xmlhttp=new XMLHttpRequest();}catch(e) {xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");}return xmlhttp;}//使用Ajaxfunction ajaxSubmit(){var xmlhttp=createXMLHttp();xmlhttp.onreadystatechange=function(){if(4==xmlhttp.readyState){if(200==xmlhttp.status){//获取从服务器端传过来的Text文本alert(xmlhttp.responseText)//获取从服务器端传过来的Text文本，并使用JSON的parseJSON函数将文本转换为javascript对象var myobj = xmlhttp.responseText.parseJSON(); //遍历javascript对象for (i = 0; i < myobj.programmers.length; i++) { alert(myobj.programmers[i].lastName);} }else {alert("no");}}}//使用标准json格式数据，创建javascript对象var people = { "programmers": [    { "firstName": "Brett", "lastName":"McLaughlin", "email": "brett@newInstance.com" },    { "firstName": "Jason", "lastName":"Hunter", "email": "jason@servlets.com" },    { "firstName": "Elliotte", "lastName":"Harold", "email": "elharo@macfaq.com" }   ], "authors": [    { "firstName": "Isaac", "lastName": "Asimov", "genre": "science fiction" },    { "firstName": "Tad", "lastName": "Williams", "genre": "fantasy" },    { "firstName": "Frank", "lastName": "Peretti", "genre": "christian fiction" }   ], "musicians": [    { "firstName": "Eric", "lastName": "Clapton", "instrument": "guitar" },    { "firstName": "Sergei", "lastName": "Rachmaninoff", "instrument": "piano" }   ] } //使用使用JSON的toJSONString函数将javascript对象转换为文本var value = people.toJSONString();//象服务器端传文本xmlhttp.open("post","UserServlet?json="+value,true); xmlhttp.send(null);return null;}</script>  </head>    <body>    <form action="UserServlet" method="post">    <input type="text" name="username" />    <input type="button" onclick="ajaxSubmit();"value="提交"/>    </form>     </body></html>

UserActionServlet.java

package action;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;public class UserActionServlet extends HttpServlet{@Overridepublic void service(HttpServletRequest arg0, HttpServletResponse arg1)throws ServletException, IOException {//System.out.println(arg0.getParameter("json"));PrintWriter writer = arg1.getWriter();//将从javascript传过来的文本读取到，然后在将文本传回到客户端writer.print(arg0.getParameter("json"));writer.flush();writer.close();}}

接下来配置web.xml文件

<?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">  <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list>  <servlet>  <servlet-name>UserServlet</servlet-name>  <servlet-class>action.UserActionServlet</servlet-class>  </servlet>  <servlet-mapping>  <servlet-name>UserServlet</servlet-name>  <url-pattern>/UserServlet</url-pattern>  </servlet-mapping></web-app>