最最基层的ajax交互代码jquery+java之间的json跨域传递以及java的json代码返回

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首先导入jar包

上面的jar包主要是用来将map或list数据转换成json字符串,传递到前台使用.

静态页面的代码:2.html

 <!DOCTYPE html>

 <html>

     <head>

         <meta charset="utf-8">

         <title>ajax</title>

           <script type="text/javascript" src="js/jquery-1.7.2.min.js"></script>

         <script type="text/javascript">

         function ajax(){

             $.ajax({

                 url:"http://192.168.6.21:8080/jsonp/servlet/Ajax",

                 data:"data=guoyansi",

                 type:"get",

                 dataType:"jsonp",

                 jsonpCallback:"jsonpCallback",//自定义的jsonp回调函数名,默认为jQuery自动生成的随机函数

                 jsonp:"callbackparam",//传递给请求处理程序或页面的,用以获得jsonp回调函数名的参数名(默认为callback)

                 error:function(){alert("服务器连接失败");},

                 success:function(data){

                     data=eval(data);

                     for(var i=0;i<data.length;i++){

                         alert(data[i])

                     }

                 }

             });

     }

 </script>

     </head>

     <body>

          <input type="button" value="提交" onclick="ajax()" /> 

     </body>

 </html>

新建servlet,服务器端的servlet---ajax.java代码:

这里的web.xml就省略了.

返回list集合(数组)

 package servlet;

 import java.io.IOException;

 import java.io.PrintWriter;

 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 Ajax extends HttpServlet {

     public void doGet(HttpServletRequest request, HttpServletResponse response)

             throws ServletException, IOException {

         doPost(request, response);

     }

     public void doPost(HttpServletRequest request, HttpServletResponse response)

             throws ServletException, IOException {

         //response.setHeader("Access-Control-Allow-Origin", "*");

         response.setContentType("text/plain");

         response.setCharacterEncoding("utf-8");

         String jsonp=request.getParameter("callbackparam");

         String name=request.getParameter("data");

         System.out.println("param:"+name);

         List<String> list=new ArrayList<String>();

         list.add("abc");

         list.add("dcc");

         list.add("1");

         list.add("2");

         list.add("3434");

         list.add("retr");

         JSONArray jsonArray=JSONArray.fromObject(list);

         String result=jsonArray.toString();

         PrintWriter writer=response.getWriter();

         writer.write(jsonp+"("+result+")");

     }

 }

跑一下:

服务器端返回map数据(json)

修改ajax.java代码

 package servlet;

 import java.io.IOException;

 import java.io.PrintWriter;

 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 net.sf.json.JSONArray;

 import net.sf.json.JSONObject;

 public class Ajax extends HttpServlet {

     public void doGet(HttpServletRequest request, HttpServletResponse response)

             throws ServletException, IOException {

         doPost(request, response);

     }

     public void doPost(HttpServletRequest request, HttpServletResponse response)

             throws ServletException, IOException {

         response.setContentType("text/plain");

         response.setCharacterEncoding("utf-8");

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

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

         String name=request.getParameter("data");

         System.out.println("param:"+name);

         Map<String, String> map=new HashMap<String, String>();

         map.put("1", "a");

         map.put("2", "b");

         map.put("3", "c");

         map.put("4", "d");

         JSONObject jsonObject=JSONObject.fromObject(map);

         String result=jsonObject.toString();

         PrintWriter writer=response.getWriter();

         writer.write(callbackparam+"("+result+")");

     }

 }

修改页面代码:

 <!DOCTYPE html>

 <html>

     <head>

         <meta charset="utf-8">

         <title>ajax</title>

           <script type="text/javascript" src="js/jquery-1.7.2.min.js"></script>

         <script type="text/javascript">

         function ajax(){

             $.ajax({

                 url:"http://192.168.6.21:8080/jsonp/servlet/Ajax",

                 data:"data=guoyansi",

                 type:"get",

                 dataType:"jsonp",

                 jsonp:"callbackparam",//传递给请求处理程序或页面的,用以获得jsonp回调函数名的参数名(默认为callback)

                 jsonpCallback:"success_jsonpCallback",//自定义的jsonp回调函数名,默认为jQuery自动生成的随机函数

                 error:function(){alert("服务器连接失败");},

                 success:function(data){

                     for(var key in data){

                         alert(key+":"+data[key]);

                     }

                 }

             });

     }

 </script>

     </head>

     <body>

          <input type="button" value="提交" onclick="ajax()" /> 

     </body>

 </html>