function getModelId(obj, dataTypeName) {


    var def = $.Deferred();

    $.ajax({
        type: "GET",
        contentType: "application/json; charset=utf-8",
        datatype: "json",
        url: “此处隐藏。。。。”,
        beforeSend: function (XMLHttpRequest) {
            XMLHttpRequest.setRequestHeader("OData-MaxVersion", "4.0");
            XMLHttpRequest.setRequestHeader("OData-Version", "4.0");
            XMLHttpRequest.setRequestHeader("Accept", "application/json");
            XMLHttpRequest.setRequestHeader("Prefer", "odata.include-annotations=\"*\",odata.maxpagesize=1");
        },
        success: function (data, textStatus, xhr) {
            var results = data;
            if (results.value.length > 0) {
                obj.ModelId = results.value[0]["productid"];
                def.resolve(obj);
            }
            else {
                def.reject("The " + dataTypeName + " data of Model " + modelName + " is not imported due to " + modelName + " is not exist.");
            }

        },
        error: function (xhr, textStatus, errorThrown) {
            def.reject("Error Info: " + textStatus + " " + errorThrown);
        }
    })

    return def.promise();

}


刚刚接触Deferred对象，上面的写法，应该是有问题的，但不清楚问题出在哪里，还望大神们指教一下。谢谢