将复杂的Java对象映射到Json数组

Question

I have an Ann class that contains a List of Anime. Anime contains attributes id, name and List of info.

Ann

package entities;

import javax.xml.bind.annotation.*;
import java.util.*;
import javax.ejb.Stateless;

@Stateless
@XmlRootElement(name = "ann")
public class Ann {

    private List<Anime> Ann = new ArrayList<Anime>();

    @XmlElement(name="anime")
    public List<Anime> getAnn() {
        return Ann;
    }

    public void setAnn(List<Anime> Ann) {
        this.Ann = Ann;
    }

    public Ann() {
        super();
    }}

I want to take Ann (list of anime objects) and parse it into Json to be sent by Gson to an ajax so that the individual elements can ultimately be used/displayed by javascript on my jsp webpage.

I got it working to some degree with:

private void returnResults(HttpServletResponse response, String searchQuery) throws IOException{

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

 try{

   for (Anime anime : annj.Unmarshalling(searchQuery).getAnn()) {

     map.put("name", anime.getName());
     map.put("id", anime.getId());

     for (Info temp : anime.getAnime()) {
       if (temp.getSrc() != null) {

         map.put("url", temp.getSrc());

       }
     }

     response.getWriter().write(new Gson().toJson(map));

  }
}catch(Exception e){} 

i send the data to :

$(document).ready(function(){
    $('#searchForm').submit(function(){

        $.ajax({
            url: 'search',
            type: 'POST',
            dataType: 'text',
            data: $('#searchForm').serialize(),
            success: function(data){

//                if(data.isValid){
//                    alert("hi");
                    $('#displaySearchResults').html("Results:" + data);
//                    $('#displaySearchResults').slideDown(500);
//                }
//                else{
//                    alert('Enter a valid search term.');
//                }
            }
        });
        return false;
    });
});

this produces:

Results:{"name":"Neon Genesis Evangelion: The End of Evangelion","id":"419","url":"http://cdn.animenewsnetwork.com/thumbnails/fit200x200/encyc/A419-28.jpg"}{"name":"Neon Genesis Evangelion: Death \u0026 Rebirth","id":"418","url":"http://cdn.animenewsnetwork.com/thumbnails/fit200x200/encyc/A418-12.jpg"}{"name":"Neon Genesis Evangelion","id":"49","url":"http://cdn.animenewsnetwork.com/thumbnails/fit200x200/encyc/A49-16.jpg"}

this is great but it isn't proper JSON format is it? shouldn't there be a comma inbetween each entry?

i am doing this because i read that you need your data to be in JSON format to display it on a webpage using javascript/jquery.

ultimately i want to be able to take this search result data and display to the user with a jquery style manipulatable list in picture format.

my question is, can you help me figure out how to format the data into a single , correct JSON string?

I have spent the last hour looking into adding a toString() method on my Ann class to try to return it's attributes directly instead of accessing the individual Anime attributes, something like this

Ann class

//    @Override
//    public String toString(){
//        
//        String masterList = ""; 
//        
//        for (Anime ann : this.Ann){
//        
//           masterList = masterList +  ann.getName();
//            
//        }
//        return masterList;
//    }

Servlet method

//        try{
//            String ann1 = annj.Unmarshalling(searchQuery).getAnn().toString(); 
//            
//            map.put("hi", ann1);
//            
//            response.getWriter().write(new Gson().toJson(map));
//            
//        }catch(Exception e){} 

This didn't seem to access the object data properly and I aborted it since I could be going down that alleyway forever and its probably unnecessary. (on 2nd thoughts it looks pretty decent.... but I don't know)

Thankyou for reading.

Answer 1

You are tying to print Map object again and again over response; thats reason you are seeing maps printed without comma. Put map objects inside ArrayList and print it. it should work.

private void returnResults(HttpServletResponse response, String searchQuery) throws IOException{

  //arraylist to hold your Mapped String values.
  ArrayList<Map> arrayOfMap = new ArrayList<Map>(); 
 try{

for (Anime anime : annj.Unmarshalling(searchQuery).getAnn()) {
        Map <String, String> map = new HashMap<String, String>();
        map.put("name", anime.getName());
                map.put("id", anime.getId());

                for (Info temp : anime.getAnime()) {
                    if (temp.getSrc() != null) {

 map.put("url", temp.getSrc());

    }
                }

         //add map to arrayList
         arrayOfMap.add(map);


  }
  //once ready, print all arraylist on response
  response.getWriter().write(new Gson().toJson(arrayOfMap));

  }catch(Exception e){} 

Once you have result at client side you can iterate over JSON to get your data printed on page;

$.each(data.result, function(listID, mapData){
     /* I am assuming you will create Lable for each String in JSON inside your HTML */
    $("#displaySearchResults > idLable").text(mapDate.id);
    $("#displaySearchResults > nameLable").text(mapDate.name);
    $("#displaySearchResults > urlLable").text(mapDate.url);

}