从Spring Controller返回数据到Ajax

Question

So I am having my add to cart for a "DVD" store button make an ajax call to my server to access the check whether there are enough DVDs in stock in the database and add it to the "cart" in the session.I feel like I have the "call" right but not too sure on how to get my spring controller to "respond".I essentially just want an object with the fields "successStatus" and "message" to be returned to the ajax to display to the user.

My button in the html

 <form method="post">
 <p>Enter quantity you would like to purchase :
<input type="number" id="quantity" name="quantity" step="any" min="1" max="${product.quantityInStock}" value="1"></input>
 </p>
<input type="submit" class="btn btn-primary"  id="addToCart"  name="button" value="Add to cart"/>
<input type="hidden" id="jsonProductId" value='${product.id}'/>
</form>

Ajax call

  $("#addToCart").click(function(event) {

        var data = {}
        data["productId"] = $("#jsonProductId").val();
       data["quantity"] = $("#quantity").val();

        $.ajax({
                 type: "POST",
                 contentType: "application/json",
                 url: "addToCart",
                 data: JSON.stringify(data),
                 dataType: 'json',
                 timeout: 600000,
                 success: function (data) {

                     //...
                 },
                 error: function (e) {

                     //...
                 }
        });
  event.preventDefault();

    });

Controller

  @Controller
  @Scope("session")
  public class CartController {
@Autowired
private Cart cart;
@Autowired
ProductService productService;



@RequestMapping(value="/addToCart", method= RequestMethod.POST)
public String searchResults(@RequestBody AddToCartPojo addToCartPojo) {
   //do something
}

@RequestMapping(value="/cart", method= RequestMethod.GET)
public String searchResults(Model model) {
model.addAttribute("cartLines",cart.getLines());
model.addAttribute("cartTotalPrice",cart.getTotalPrice());
    return "cart";
}

AddToCartPojo

public class AddToCartPojo {
private long productId;
private int quantity;

public long getProductId() {
    return productId;
}

public void setProductId(long productId) {
    this.productId = productId;
}

public int getQuantity() {
    return quantity;
}

public void setQuantity(int quantity) {
    this.quantity = quantity;
}
}

Answer 1

Just change your controller a bit

@RestController
@Scope("session")
public class CartController {

    @Autowired
    private Cart cart;
    @Autowired
    ProductService productService;

    @RequestMapping(value="/addToCart", method= RequestMethod.POST)
    public String searchResults(@RequestBody AddToCartPojo addToCartPojo) {
       //do something

       String responseMessage = "success";
       return responseMessage;
    }
}

I added @RestController annotation instead of @Controller , which implicitly adds @ResponseBody to every method in this class.

@Response Body - Annotation that indicates a method return value should be bound to the web response body. Supported for annotated handler methods in Servlet environments.

No need to send status separately. Instead HTTP status could be used. If you have 200 then success.

Answer 2

If you use @Controller without @ResponseBody , after requests are processed by the CartController and the response is returned to the DispatcherServlet with logical view name (In your example it is "cart"). Then return to the view resolver prepared the view based on your configuration decide the which configuration (JSP, Velocity, PDF etc.) to be invoked. (For example, use cart.jsp page).

@ResponseBody - Annotation that indicates a method return value should be bound to the web response body. Supported for annotated handler methods in Servlet environments.

So if you annotate method with @ResponseBody response will be returned to the browser and will be available in success: function(data) as data param.