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  • 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>
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  • 原文地址:https://www.cnblogs.com/guoyansi19900907/p/4593455.html
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