将Servlet传递的复杂对象存储到JavaScript中的数组中

Question

I have a servlet that passes an ArrayList into a jsp page that receives it and places it in an Array, but i can't access the parameters inside Loc if i store them in an array like this:

var locations = new Array();
<c:forEach items="${photosName}" var="photo" varStatus="loop">
    locations["${loop.index}"] = "${photo}";
</c:forEach>

the variable photo contains attributes like latitude, longitude and accuracy that i wish to store in the locations array. But if i store them like this how can i access them in other parts of code.

Example of what i want to do:

locations[i].latitude
locations[i].longitude
locations[i].accuracy

Any help is welcome :)

Tried this now:

var locations = new Array();
<c:forEach items="${photosName}" var="photo" varStatus="loop">
    locations["${loop.index}"] = JSON.stringify("${photo}");
</c:forEach>
alert("latitude: "+locations[0].latitude+ " longitude: "+locations[0].longitude);

It printed latitude: undefined longitude: undefined. Do i need to import something for the json.stringify to work?

Photo object in jsp is represented by this class:

@Entity
public class Loc implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.TABLE)
    private long id;
    private double latitude;
    private double longitude;
    private long time;
    private double accuracy;
    private int processed;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public double getLatitude() {
        return this.latitude;
    }

    public void setLatitude(double latitude) {
        this.latitude = latitude;
    }

    public double getLongitude() {
        return this.longitude;
    }

    public void setLongitude(double longitude) {
        this.longitude = longitude;
    }

    public long getTime() {
        return this.time;
    }

    public void setTime(long time) {
        this.time = time;
    }

    @Override
    public String toString() {
        return "latitude: " + latitude + " longitude: " + longitude + "time: "
                + time;
    }

    public double getAccuracy() {
        return accuracy;
    }

    public void setAccuracy(double accuracy) {
        this.accuracy = accuracy;
    }

    public int getProcessed() {
        return processed;
    }

    public void setProcessed(int processed) {
        this.processed = processed;
    }
}

Answer 1

Try locations["${loop.index}"] = {JSON.stringify("${photo}")}; . Then you can access the attributes as you wrote:

locations[i].latitude
locations[i].longitude
locations[i].accuracy

Note: photo is a string representation of a JSONObject. Like this:

JSONObject jsonPhoto = gson.toJson(photoObj) //photoObj is instance of your java photo object class
String photo = jsonPhoto.toString();

For converting an object to json object you can use GSON library. Here is link to a nice tutorial.

If you have list of Java phtoObjects you can do like this in your servlet:

<%@ page import="com.google.gson.Gson" %>   
<%GSON gson = new Gson();%>    
var photoArray = JSON.stringify(<%=gson.toJson(phtoObjects).toString()%>);