在淘宝联盟P28视频中，实现根据发现页分类ID获取分类内容那里返回的数据只有中文和数字，其他的好多都为null。自己用浏览器打开了URL，返回是有效果的，不知道代码哪里出错了。

相关代码：

//根据分类ID去加载内容
Retrofit retrofit = RetrofitManager.getOurInstance().getRetrofit();
Api api = retrofit.create(Api.class);
Integer targetPage = pagesInfo.get(categoryId);
if (targetPage == null) {
    targetPage = DEFAULT_PAGE;
    pagesInfo.put(categoryId, DEFAULT_PAGE);
}
String homePagerUrl = UrlUtils.createHomePagerUrl(categoryId, targetPage);
LogUtils.d(this, "home page -->"+homePagerUrl);
Call<HomePagerContent> task = api.getHomePagerContent(homePagerUrl);
task.enqueue(new Callback<HomePagerContent>() {
    @Override
    public void onResponse(Call<HomePagerContent> call, Response<HomePagerContent> response) {
        int code = response.code();
        LogUtils.d(this,"code -->"+code);
        if (code == HttpURLConnection.HTTP_OK){
            HomePagerContent pagerContent = response.body();
            LogUtils.d(this, "page content -->"+pagerContent.toString());
            //把数据给到UI
            handleHomePageContentResult(pagerContent,categoryId);
        }else {
            //网络错误
            hadleNetWorkError(categoryId);
        }
    }
URL为：https://api.sunofbeaches.com/shop/discovery/9649/1

2022-03-29 20:58:41.673 21243-21243/com.example.taobaounion D/: page content -->HomePagerContent{success=true, code=10000, message='获取成功.', data=[DataDTO{categoryId=0, categoryName=null, clickUrl='null', commissionRate='null', couponAmount=0, couponClickUrl='null', couponEndTime='null', couponInfo=null, couponRemainCount=0, couponShareUrl='null', couponStartFee='null', couponStartTime='null', couponTotalCount=0, itemDescription='null', itemId=0, levelOneCategoryId=0, levelOneCategoryName='null', nick='null', pictUrl='null', sellerId=0, shopTitle='null', smallImages=null, title='鑫炳记原味太谷饼整箱山西好吃的零食包邮零食特产面包点心糕点', userType=0, volume=20000, zkFinalPrice='null'}, DataDTO{categoryId=0, categoryName=null, clickUrl='null', commissionRate='null', couponAmount=0, couponClickUrl='null', couponEndTime='null', couponInfo=null, couponRemainCount=0, couponShareUrl='null', couponStartFee='null', couponStartTime='null', couponTotalCount=0, itemDescription='null', itemId=0, levelOneCategoryId=0, levelOneCategoryName='null', nick='null', pictUrl='null', sellerId=0, shopTitle='null', smallImages=null, title='【蜜蜂惊喜社】七姊武汉热干面正宗湖北特产碱水面挂面速食干拌面', userType=0, volume=30000, zkFinalPrice='null'}, DataDTO{categoryId=0, categoryName=null, clickUrl='null', commissionRate='null', couponAmount=0, couponClickUrl='null', couponEndTime='null', couponInfo=null, couponRemainCount=0, couponShareUrl='null', couponStartFee='null', couponStartTime='null', couponTotalCount=0, itemDescription='null', itemId=0, levelOneCategoryId=0, levelOneCategoryName='null', nick='null', pictUrl='null', sellerId=0, shopTitle='null', smallImages=null, title='螺满地广西螺蛳粉300g整箱装 柳州正宗速食袋装螺狮粉螺丝粉', userType=0, volume=300000, zkFinalPrice='null'}, DataDTO{categoryId=0, categoryName=null, clickUrl='null', commissionRate='null', couponAmount=0, couponClickUrl='null', couponEndTime='null', couponInfo=null, couponRemainCount=0, couponShareUrl='null', couponStartFee='null', couponStartTime='null', couponTotalCount=0, itemDescription='null', itemId=0, levelOneCategoryId=0, levelOneCategoryName='null', nick='null', pictUrl='null', sellerId=0, shopTitle='null', smallImages=null, title='2021年新米东北米黑龙江农家米粳米正宗五常稻花香2号大米5kg包邮', userType=0, volume=1000, zkFinalPrice='null'}, DataDTO{categoryId=0, categoryName=null, clickUrl='null', commissionRate='null', couponAmount=0, couponClickUrl='null', couponEndTime='null', couponInfo=null, couponRemainCount=0, couponShareUrl='null', couponStartFee='null', couponStartTime='null', couponTotalCount=0, itemDescription='null', itemId=0, levelOneCategoryId=0, levelOneCategoryName='null', nick='null', pictUrl='null', sellerId=0, shopTitle='null', smallImages=null, title='黄金搭档B族维生素全族复合维生素b b1 b2 b6官方旗舰店正品vb搭c', userType=0, volume=50000, zkFinalPrice='null'}, DataDTO{categoryId=0, categoryName=null, clickUrl='null', commissionRate='null', couponAmount=0, couponClickUrl='null', couponEndTime='null', couponInfo=null, couponRemainCount=0, couponShareUrl='null', couponStartFee='null', couponStartTime='null', couponTotalCount=0, itemDescription='null', itemId=0, levelOneCategoryId=0, levelOneCategoryName='null', nick='null', pictUrl='null', sellerId=0, shopTitle='null', smallImages=null, title='寻么玉米新鲜糯玉米东北粘低黏黄糯甜玉米棒真空10支肥非转代餐脂', userType=0, volume=30000, zkFinalPrice='null'}, DataDTO{categoryId=0, categoryName=null, clickUrl='null', commissionRate='null', couponAmount=0, couponClickUrl='null', couponEndTime='null', couponInfo=null, couponRemainCount=0, couponShareUrl='null', couponStartFee='null', couponStartTime='null', couponTotalCount=0, itemDescription='null', itemId=0, levelOneCategoryId=0, levelOneCategoryName='null', nick='null', pictUrl='null', sellerId=0, shopTitle='null', smallImages=null, title='肖战同款隅田川冷萃咖啡袋泡意式拿铁黑咖啡粉奶粹热泡咖啡