无法使用retrofit2将文件上载到服务器

implementation 'com.squareup.retrofit2:retrofit:2.x.x'
implementation 'com.squareup.retrofit2:converter-gson:2.x.x'
implementation 'com.squareup.okhttp3:okhttp:4.x.x'

public interface FileUploadService {
    @Multipart
    @POST("upload")
    Call<ResponseBody> uploadFile(@Part MultipartBody.Part file);
}

OkHttpClient client = new OkHttpClient.Builder()
        .build();

Retrofit retrofit = new Retrofit.Builder()
        .baseUrl("http://your-server-url.com/")
        .client(client)
        .addConverterFactory(GsonConverterFactory.create())
        .build();

FileUploadService service = retrofit.create(FileUploadService.class);

File file = new File("path/to/your/file");
RequestBody requestBody = RequestBody.create(MediaType.parse("multipart/form-data"), file);
MultipartBody.Part filePart = MultipartBody.Part.createFormData("file", file.getName(), requestBody);

Call<ResponseBody> call = service.uploadFile(filePart);

call.enqueue(new Callback<ResponseBody>() {
    @Override
    public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
        // 处理上传成功的响应
    }

    @Override
    public void onFailure(Call<ResponseBody> call, Throwable t) {
        // 处理上传失败的情况
    }
});