问人脸识别接口中为什么会提示常量字符串过长呢？

  ClientProfile clientProfile = new ClientProfile();
            clientProfile.setHttpProfile(httpProfile);
            // 实例化要请求产品的client对象,clientProfile是可选的
            IaiClient client = new IaiClient(cred, "ap-beijing", clientProfile);
            // 实例化一个请求对象,每个接口都会对应一个request对象
            CompareFaceRequest req = new CompareFaceRequest();
            // 返回的resp是一个CompareFaceResponse的实例，与请求对象对应
             req.setImageA("data:image/jpg;base64,/9j/4AAQSkZJRgABAgEBLAEsAAD/4RdgRXh.........");