java servlet+jquery+json学习小例子

时间：2022-05-16 06:57:24

引入JSON的jar包:

java servlet+jquery+json学习小例子

注意，如果包不全，页面请求servlet时，jquery ajax会返回error：function

弹出error occured!!!

HTML Code:

 <%@ page language="java" pageEncoding="utf-8"%>

 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

 <html>

 <head>

 <title>jquery ajax</title>

 <meta http-equiv="pragma" content="no-cache">

 <meta http-equiv="cache-control" content="no-cache">

 <meta http-equiv="expires" content="">

 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">

 <meta http-equiv="description" content="This is my page">

 <script src="jquery/jquery-1.8.2.min.js" type="text/javascript"></script>

 <script language="javascript">

     $(function(){

         $('.sumbit').click(function(){

             var v = $('#account').val();

             alert(v);

             if($('#account').val().length==){

                 $('.hint').text("用户名不能位空").css({"background-color":"green"});

             }else{

                 $.ajax({

                         type:'get',

                     url:'jqueryAjax',

                     data:{account:$('#account').val()},

                     dataType:'json', //很重要!!!.预期服务器返回的数据类型 ,

                     success:function(data){

                         $.each(data.jsonArray,function(index){

                             $.each(data.jsonArray[index],function(key,value){

                                 alert(key+":"+value)

                             });

                         });     

                         $('body').append("<div>"+data.account+"</div>").css("color","red");

                     },

                     error:function(){

                         alert("error occured!!!");

                     }     

                 });

             }

         });

     });

 </script>

 </head>    

 <body>

 <h3 align="center">jquery AjaX</h3>

 <hr>

 <label>请输入你的账户 ：</label>

 <input id="account" name="account" type="text">

 <input class="sumbit" type="button" value="检测">

 <div class="hint"></div>

 </body>

 </html>

dataType:'json', //很重要!!!.预期服务器返回的数据类型 ,这句代码注释掉,也正常运行!

不知是否是servlet中写了这句代码的原因:

response.setContentType("application/x-json");(网上找下原因)

servlet Code：JqueryAjaxServlet.java

 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;  

 import net.sf.json.JSONArray;

 import net.sf.json.JSONObject;  

 /**

  * Author: YangT

  * Version: 1.0

  * Create: 2013-3-13 上午10:34:58

  */

 public class JqueryAjaxServlet extends HttpServlet {  

     public void doGet(HttpServletRequest request, HttpServletResponse response)

             throws ServletException, IOException {

         System.out.println("JqueryAjaxServlet :  begin");  

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

         String account = request.getParameter("account");

         System.out.println("account :" + account);  

         JSONObject json = new JSONObject();

         JSONArray jsonArray = new JSONArray();  

         JSONObject member = null;

         for (int i = ; i < ; i++) {

             member = new JSONObject();

             member.put("name", "yangting" + i);

             member.put("age",  + i);

             jsonArray.add(member);

         }

         json.put("jsonArray", jsonArray);

         json.put("account", account);  

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

                 response.setContentType("application/x-json");

         PrintWriter pw = response.getWriter();

         pw.print(json.toString());  

         System.out.println("json array :" + jsonArray.toString());

         System.out.println("json object :" + json.toString());

         System.out.println("JqueryAjaxServlet : end");  

         pw.close();  

     }  

     public void doPost(HttpServletRequest request, HttpServletResponse response)

             throws IOException, ServletException {

         this.doGet(request, response);

     }   

 }

web.xml

 <?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" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">  

     <servlet>

         <servlet-name>JqueryAjaxServlet</servlet-name>

         <servlet-class>JqueryAjaxServlet</servlet-class>

     </servlet>

     <servlet-mapping>

         <servlet-name>JqueryAjaxServlet</servlet-name>

         <url-pattern>/jqueryAjax</url-pattern>

     </servlet-mapping>  

 </web-app>

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