Spring MVC + Ajax错误400

我在Spring MVC上有一个简单的Java应用程序，并将ajax请求发送到Spring控制器。当我在AJAX调用中设置标头“ Accept”，“ application / json”和“ Content-Type”，“ application / json; charset = utf-8”时，在dubugger中出现错误400，在删除它时，出现错误415。

如果我将控制器方法签名更改为public String logoutPage（@RequestBody String obyavleniye），则会得到JSON字符串。控制器中的解析请求会出现什么问题？

JS方法：

$("#advertForm").submit(function(e) {
        e.preventDefault();
        var token = $("meta[name='_csrf']").attr("content");
        var header = $("meta[name='_csrf_header']").attr("content");
        var obyavleniye = {
            title: "Title",
            price: "80",
            description: "desc",
            date: "2016-11-07 18:30:21",
            authorid: "2",
            category: "A",
            state: "new",
            img1: "http",
            img2: "http",
            img3: "http",
            img4: "http",
        };
        var post_data = JSON.stringify(obyavleniye);

        console.log(post_data);
        $.ajax({
            url : "/upload",
            type: "POST",
            dataType: 'json',
            data: post_data,
            beforeSend: function(xhr) {
                xhr.setRequestHeader("Accept", "application/json");
                xhr.setRequestHeader("Content-Type", "application/json;charset=utf-8");
                xhr.setRequestHeader(header, token);
            },
            complete: function() {
                console.log("Sent");
            },
            success: function (response) {
                console.log("success");
                console.log("response" + response);
            },
            error: function (data) {
                console.log("error");
                console.log(data);
            }
        });
    });

控制器方式：

@ResponseBody
    @RequestMapping(value="/upload", method = RequestMethod.POST)
    public String logoutPage (@RequestBody Advert obyavleniye) {
//    public String logoutPage (@RequestBody String obyavleniye) {
        System.out.println("Enter: " + obyavleniye);
        this.advertService.addAdvert(obyavleniye);
//        return "{\"msg\":\"success\"}";
        return "{\"title\":\"Title\",\"price\":\"80\",\"description\":\"normm\",\"date\":\"2016-11-07 18:30:21\",\"authorid\":\"2\",\"category\":\"A\",\"state\":\"new\",\"img1\":\"http\",\"img2\":\"http\",\"img3\":\"http\",\"img4\":\"http\"}";
    }