Spring MVC return ajax response using Jackson
- by anshumn
I have a scenario where I am filling a dropdown box in JSP through AJAX response from the server. In the controller, I am retuning a Collection of Product objects and have annotated the return type with @ResponseBody.
Controller - 
@RequestMapping(value="/getServicesForMarket", method = RequestMethod.GET)
public @ResponseBody Collection<Product> getServices(@RequestParam(value="marketId", required=true) int marketId) {
    Collection<Product> products = marketService.getProducts(marketId);
    return products;
}
And Product is 
@Entity
@Table(name = "PRODUCT")
public class Product implements Serializable {
    private static final long serialVersionUID = 1L;
    private int id;
    private Market market;
    private Service service;
    private int price;
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    @ManyToOne(fetch=FetchType.LAZY)
    @JoinColumn(name = "MARKET_ID")
    public Market getMarket() {
        return market;
    }
    public void setMarket(Market market) {
        this.market = market;
    }
    @ManyToOne(fetch=FetchType.LAZY)
    @JoinColumn(name = "SERVICE_ID")
    public Service getService() {
        return service;
    }
    public void setService(Service service) {
        this.service = service;
    }
    @Column(name = "PRICE")
    public int getPrice() {
        return price;
    }
    public void setPrice(int price) {
        this.price = price;
    }
}
Service is
@Entity
@Table(name="SERVICE")
public class Service implements Serializable {
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private int id;
    private String name;
    private String description;
    @Id
    @GeneratedValue
    @Column(name="ID")
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    @Column(name="NAME")
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    @Column(name="DESCRIPTION")
    public String getDescription() {
        return description;
    }
    public void setDescription(String description) {
        this.description = description;
    }
}
In the JSP, I need to get the data from the service field of Product also. So I in my JQuery callback function, I have written like product.service.description to get the data.
It seems that by default Jackson is not mapping the associated service object (or any other custom object). Also I am not getting any exception. In the JSP, I do not get the data. It is working fine when I return Collection of some object which does not contain any other custom objects as its fields. 
Am I missing any settings for this to work?
Thanks!