我正在尝试使用Android的Retrofit 2发送HTTP请求，该请求应该得到一个PDF文件作为响应。发送请求后，该PDF文件应在后台下载到用户的设备。

我尝试使用教程来执行此操作，但未成功。

  

这是我的 GetFileApi ：

 @GET("index.php/get-file")
 Call<ResponseBody> getPDF(@Header("authorization") String token,@Body String Id);

  

这是我的 ServiceGenerator 类：

 public class ServiceGenerator {

    public static final String API_BASE_URL = "https://url/";

    private static OkHttpClient.Builder httpClient = new OkHttpClient.Builder();

    private static Retrofit.Builder builder =
            new Retrofit.Builder()
                    .baseUrl(API_BASE_URL)
                    .addConverterFactory(GsonConverterFactory.create());

    public static <S> S createService(Class<S> serviceclass){
        Retrofit retrofit = builder.client(httpClient.build()).build();
        return retrofit.create(serviceclass);
    }

}

  

这是我的功能：

private void downloadFile(){
        GetFileAPI apiInterface = ServiceGenerator.createService(GetFileAPI.class);

        Call<ResponseBody> call = apiInterface.getPDF(token,id);

        call.enqueue(new Callback<ResponseBody>() {
            @Override
            public void onResponse(Call<ResponseBody> call,Response<ResponseBody> response) {
                if (response.isSuccessful()){
                    boolean writtenToDisk = writeResponseBodyToDisk(response.body());

                    Log.d("File downloaded! ",String.valueOf(writtenToDisk));
                }
            }

            @Override
            public void onFailure(Call<ResponseBody> call,Throwable t) {

            }
        });
    }

    private boolean writeResponseBodyToDisk(ResponseBody body) {
        try {
            // todo change the file location/name according to your needs
            File futureStudioIconFile = new File(getExternalFilesDir(null) + File.separator + "download.pdf");

            InputStream inputStream = null;
            OutputStream outputStream = null;

            try {
                byte[] fileReader = new byte[4096];

                long fileSize = body.contentLength();
                long fileSizeDownloaded = 0;

                inputStream = body.byteStream();
                outputStream = new FileOutputStream(futureStudioIconFile);

                while (true) {
                    int read = inputStream.read(fileReader);

                    if (read == -1) {
                        break;
                    }

                    outputStream.write(fileReader,read);

                    fileSizeDownloaded += read;

                    Log.d("File Download: ",fileSizeDownloaded + " of " + fileSize);
                }

                outputStream.flush();

                return true;
            } catch (IOException e) {
                return false;
            } finally {
                if (inputStream != null) {
                    inputStream.close();
                }

                if (outputStream != null) {
                    outputStream.close();
                }
            }
        } catch (IOException e) {
            return false;
        }
    }

我得到了这个错误，尽管这不是应用程序无法正常运行的唯一原因。必须发送令牌和 id ，令牌在 @Header 中发送，ID在 @Body 。

java.lang.IllegalArgumentException: Non-body HTTP method cannot contain @Body.