java代码中后台向前台传递list或map集合案例

时间：2021-09-01 20:45:09

导入jar包

java代码中后台向前台传递list或map集合案例

新建一个servert传递map集合

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");

         //模拟数据库数据

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

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

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

         map.put("3", "王东");

         map.put("4", "毛东");

         //前台传过来的参数

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

         JSONObject re=JSONObject.fromObject(map);

         String result=re.toString();

         System.out.println("result"+result);

         PrintWriter writer=response.getWriter();

         writer.write(result);//返回json数组

         writer.flush();

         writer.close();

     }

 }

前台页面:

 <!DOCTYPE html>

 <html>

   <head>

     <title>2.html</title>

     <meta charset="utf-8">

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

     <script type="text/javascript">

     function ajax(){

         $.ajax({

             url:"servlet/Ajax",

             data:"data=r",

             type:"post",

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

             success:function(data){

                 data=eval(data);

                 for(var key in data){

                     alert(data)

                 }

             }

         });

     }

     </script>

   </head>

   <body>

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

   </body>

 </html>

修改ajax.java,向前台传递list

 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");

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

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

         list.add("afds");

         list.add("反对反对");

         list.add("");

         JSONArray jsonArray=JSONArray.fromObject(list);

         String result=jsonArray.toString();

         System.out.println(result);

         PrintWriter writer=response.getWriter();

         writer.write(result);//返回json数组

         writer.flush();

         writer.close();

     }

 }

静态页面代码:

 <!DOCTYPE html>

 <html>

   <head>

     <title>2.html</title>

     <meta charset="utf-8">

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

     <script type="text/javascript">

     function ajax(){

         $.ajax({

             url:"servlet/Ajax",

             data:"data=r",

             type:"post",

             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>

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