java代码中后台向前台传递list或map集合案例

导入jar包

新建一个servert传递map集合

ajax.java代码:

 1 package servlet;
 2 
 3 import java.io.IOException;
 4 import java.io.PrintWriter;
 5 import java.util.ArrayList;
 6 import java.util.HashMap;
 7 import java.util.List;
 8 import java.util.Map;
 9 
10 import javax.servlet.ServletException;
11 import javax.servlet.http.HttpServlet;
12 import javax.servlet.http.HttpServletRequest;
13 import javax.servlet.http.HttpServletResponse;
14 
15 import net.sf.json.JSONArray;
16 import net.sf.json.JSONObject;
17 
18 public class Ajax extends HttpServlet {
19     public void doGet(HttpServletRequest request, HttpServletResponse response)
20             throws ServletException, IOException {
21         doPost(request, response);
22     }    
23     public void doPost(HttpServletRequest request, HttpServletResponse response)
24             throws ServletException, IOException {        
25         response.setContentType("text/plain");
26         response.setCharacterEncoding("utf-8");        
27         //模拟数据库数据
28         Map<String, String> map=new HashMap<String, String>();
29         map.put("1", "a");
30         map.put("2", "ab");
31         map.put("3", "王东");
32         map.put("4", "毛东");    
33         //前台传过来的参数
34         String data=request.getParameter("data");                    
35         JSONObject re=JSONObject.fromObject(map);
36         String result=re.toString();
37         System.out.println("result"+result);
38         PrintWriter writer=response.getWriter();
39         writer.write(result);//返回json数组
40         writer.flush();
41         writer.close();
42     }
43 
44 }

前台页面:

 1 <!DOCTYPE html>
 2 <html>
 3   <head>
 4     <title>2.html</title>
 5     <meta charset="utf-8">
 6     <script type="text/javascript" src="js/jquery-1.7.2.min.js"></script>
 7     <script type="text/javascript">
 8     function ajax(){
 9         $.ajax({
10             url:"servlet/Ajax",
11             data:"data=r",
12             type:"post",
13             error:function(){alert("服务器连接失败");},
14             success:function(data){                
15                 data=eval(data);
16                 for(var key in data){
17                     alert(data)
18                 }
19             }
20         });
21     }
22     </script>
23   </head>
24   
25   <body>
26      <input type="button" value="提交" onclick="ajax()" /> 
27   </body>
28 </html>

修改ajax.java,向前台传递list

 1 package servlet;
 2 
 3 import java.io.IOException;
 4 import java.io.PrintWriter;
 5 import java.util.ArrayList;
 6 import java.util.HashMap;
 7 import java.util.List;
 8 import java.util.Map;
 9 
10 import javax.servlet.ServletException;
11 import javax.servlet.http.HttpServlet;
12 import javax.servlet.http.HttpServletRequest;
13 import javax.servlet.http.HttpServletResponse;
14 
15 import net.sf.json.JSONArray;
16 import net.sf.json.JSONObject;
17 
18 public class Ajax extends HttpServlet {
19     public void doGet(HttpServletRequest request, HttpServletResponse response)
20             throws ServletException, IOException {
21         doPost(request, response);
22     }    
23     public void doPost(HttpServletRequest request, HttpServletResponse response)
24             throws ServletException, IOException {        
25         response.setContentType("text/plain");
26         response.setCharacterEncoding("utf-8");
27         List<String> list=new ArrayList<String>();        
28         String data=request.getParameter("data");
29         list.add("afds");
30         list.add("反对反对");
31         list.add("");
32             
33         JSONArray jsonArray=JSONArray.fromObject(list);
34         String result=jsonArray.toString();
35         System.out.println(result);
36         PrintWriter writer=response.getWriter();
37         writer.write(result);//返回json数组
38         writer.flush();
39         writer.close();
40     }
41 
42 }

静态页面代码:

 1 <!DOCTYPE html>
 2 <html>
 3   <head>
 4     <title>2.html</title>
 5     <meta charset="utf-8">
 6     <script type="text/javascript" src="js/jquery-1.7.2.min.js"></script>
 7     <script type="text/javascript">
 8     function ajax(){
 9         $.ajax({
10             url:"servlet/Ajax",
11             data:"data=r",
12             type:"post",
13             error:function(){alert("服务器连接失败");},
14             success:function(data){                
15                 data=eval(data);                
16                  for(var i=0;i<data.length;i++){
17                     alert(data[i]);
18                 } 
19                 
20             }
21         });
22     }
23     </script>
24   </head>
25   
26   <body>
27      <input type="button" value="提交" onclick="ajax()" /> 
28   </body>
29 </html>