服务器端response返回多条数据，客户端怎么接收？

Question

服务器端返回了三条数据，客户端通过解析json只能获得一条数据，然后通过浏览器访问就能看到三条，以下是客户端，服务器端的代码，求大佬指教

Answer 1

服务器端代码
 protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("application/json;charset=utf-8");
         request.setCharacterEncoding("utf-8");
         response.setCharacterEncoding("utf-8");
          PrintWriter out = response.getWriter();     //获得请求中传来的用户名和密码
         
            String username=request.getParameter("username").trim();    
            List<User> lst2 = UserDAO.getOracleFindAll(username);  
            User user;
              JSONObject a= new JSONObject();
       
          
          for(int i=0;i<lst2.size();i++){
              user=lst2.get(i);
              String classname=user.getclassname();
              String coursename=user.getcoursename();
              String num=user.getnum();
              String requested=user.getrequested();
              a.put("username", username);
              a.put("classname", classname);
              a.put("coursename", coursename);
              a.put("num", num);
              a.put("requested", requested); 
              out = response.getWriter();
              out.println(a);           
          }
          
    }

Answer 2

android端代码
 RequestQueue mQueue = Volley.newRequestQueue(MainActivity.this);
        JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(jsonurl, null, new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {
                try {                    String classname;
                    String coursename;                     classname= new String(new String(response.getString("classname")));
                     coursename =new String(new String(response.getString("coursename")));
                        classname a = new classname(classname, coursename);
                       System.out.println(coursename);                        classnameList.add(a);                Adapter adapter=new Adapter(classnameList);                    recyclerView.setAdapter(adapter);
                } catch (JSONException e) {                    Log.e("json错误",e.getMessage());
                }
            }
        },

Answer 3

图都糊了QAQ.
可是我想知道怎么接收的