UPDATE：

这是我的代码：

FileDownloadService.java

public interface FileDownloadService {
    @GET(Constants.UPLOADS_DIRECTORY + "/{filename}")
    @Streaming
    Call<ResponseBody> downloadRetrofit(@Path("filename") String fileName);
}

MainActivity.java （ @Blackbelt 的解决方案）

private void downloadFile(String filename) {
    FileDownloadService service = ServiceGenerator
            .createService(FileDownloadService.class, Constants.SERVER_IP_ADDRESS);
    Call<ResponseBody> call = service.downloadRetrofit("db90408a4bb1ee65d3e09d261494a49f.jpg");

    call.enqueue(new Callback<ResponseBody>() {
        @Override
        public void onResponse(final Response<ResponseBody> response, Retrofit retrofit) {
            try {
                InputStream is = response.body().byteStream();
                FileOutputStream fos = new FileOutputStream(
                        new File(Environment.getExternalStorageDirectory(), "image.jpg")
                );
                int read = 0;
                byte[] buffer = new byte[32768];
                while ((read = is.read(buffer)) > 0) {
                    fos.write(buffer, 0, read);
                }

                fos.close();
                is.close();
            } catch (Exception e) {
                Toast.makeText(MainActivity.this, "Exception: " + e.toString(), Toast.LENGTH_LONG).show();
            }
        }

        @Override
        public void onFailure(Throwable t) {
            Toast.makeText(MainActivity.this, "Failed to download file...", Toast.LENGTH_LONG).show();
        }
    });
}

当USB调试处于活动状态时，我得到 FileNotFoundException ，＆amp;一个 NetworkOnMainThreadException 。

MainActivity.java：（ @Emanuel 的解决方案）

private void downloadFile(String filename) {
    FileDownloadService service = ServiceGenerator
            .createService(FileDownloadService.class, Constants.SERVER_IP_ADDRESS);
    Call<ResponseBody> call = service.downloadRetrofit("db90408a4bb1ee65d3e09d261494a49f.jpg");

    call.enqueue(new Callback<ResponseBody>() {
        @Override
        public void onResponse(final Response<ResponseBody> response, Retrofit retrofit) {
            Log.i(TAG, "external storage = " + (Environment.getExternalStorageState() == null));
            Toast.makeText(MainActivity.this, "Downloading file... " + Environment.getExternalStorageDirectory(), Toast.LENGTH_LONG).show();

            File file = new File(Environment.getDataDirectory().toString() + "/aouf/image.jpg");
            try {
                file.createNewFile();
                Files.asByteSink(file).write(response.body().bytes());
            } catch (Exception e) {
                Toast.makeText(MainActivity.this,
                        "Exception: " + e.toString(),
                        Toast.LENGTH_LONG).show();
            }
        }

        @Override
        public void onFailure(Throwable t) {
            Toast.makeText(MainActivity.this, "Failed to download file...", Toast.LENGTH_LONG).show();
        }
    });
}

我收到 FileNotFoundException 。

Answer 1

这是一个显示如何下载Retrofit JAR文件的小例子。您可以根据自己的需要进行调整。

这是界面：

import com.squareup.okhttp.ResponseBody;
import retrofit.Call;
import retrofit.http.GET;
import retrofit.http.Path;

interface RetrofitDownload {
    @GET("/maven2/com/squareup/retrofit/retrofit/2.0.0-beta2/{fileName}")
    Call<ResponseBody> downloadRetrofit(@Path("fileName") String fileName);
}

这是一个使用接口的Java类：

import com.google.common.io.Files;
import com.squareup.okhttp.ResponseBody;
import retrofit.Call;
import retrofit.Callback;
import retrofit.Response;
import retrofit.Retrofit;

import java.io.File;
import java.io.IOException;

public class Main {

    public static void main(String... args) {
        Retrofit retrofit = new Retrofit.Builder().
                baseUrl("http://repo1.maven.org").
                build();

        RetrofitDownload retrofitDownload = retrofit.create(RetrofitDownload.class);

        Call<ResponseBody> call = retrofitDownload.downloadRetrofit("retrofit-2.0.0-beta2.jar");

        call.enqueue(new Callback<ResponseBody>() {
            @Override
            public void onResponse(Response<ResponseBody> response, Retrofit retrofitParam) {
                File file = new File("retrofit-2.0.0-beta2.jar");
                try {
                    file.createNewFile();
                    Files.asByteSink(file).write(response.body().bytes());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void onFailure(Throwable t) {
            }
        });
    }
}

Answer 2

下载文件，您可能希望响应的原始sdcard和写入是T上的内容。为此，您应使用ResponseBody作为Call<ResponseBody>作为返回类型Retrofit。然后，您将enqueue用于Callback<ResponseBody>

onResponse

以及@Override public void onResponse(final Response<ResponseBody> response, Retrofit retrofit) {

时

InputStream

被调用，您可以使用response.byteStream()检索Sub Test() Dim IE As Object Set IE = CreateObject("InternetExplorer.Application") With IE .Visible = True .Navigate "http://www.marketwatch.com/investing/stock/aapl/analystestimates" ' should work for any URL Do Until .ReadyState = 4: DoEvents: Loop x = .document.body.innertext y = InStr(1, x, "Average Target Price:") Z = Mid(x, y, 6) Range("A1").Value = Trim(Z) .Quit End With End Sub，从中读取，并在SD卡上写下您所读取的内容（看看here）

Answer 3

如果有人偶然发现这个回应，那么我就是如何使用rx结合改造来做到的。每个下载的文件都被缓存，并且具有相同URL的任何后续请求将返回已下载的文件。

为了使用它，只需订阅此observable并传递您的网址。这会将您的文件保存在下载目录中，因此如果您的应用面向API 23或更高版本，请务必询问权限。

  public Observable<File> getFile(final String filepath) {
    URL url = null;
    try {
        url = new URL(filepath);
    } catch (MalformedURLException e) {
        e.printStackTrace();
    }
    final String name = url.getPath().substring(url.getPath().lastIndexOf("/") + 1);
    final File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS), name);
    if (file.exists()) {
        return Observable.just(file);
    } else {
        return mRemoteService.getFile(filepath).flatMap(new Func1<Response<ResponseBody>, Observable<File>>() {
            @Override
            public Observable<File> call(final Response<ResponseBody> responseBodyResponse) {
                return Observable.create(new Observable.OnSubscribe<File>() {
                    @Override
                    public void call(Subscriber<? super File> subscriber) {
                        try {

                            final File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS).getAbsoluteFile(), name);

                            BufferedSink sink = Okio.buffer(Okio.sink(file));
                            sink.writeAll(responseBodyResponse.body().source());
                            sink.flush();
                            sink.close();
                            subscriber.onNext(file);
                            subscriber.onCompleted();
                            file.deleteOnExit();
                        } catch (IOException e) {
                            Timber.e("Save pdf failed with error %s", e.getMessage());
                            subscriber.onError(e);
                        }
                    }
                });
            }
        });
    }
}

改编部分电话

@Streaming
@GET
Observable<retrofit2.Response<ResponseBody>> getFile(@Url String fileUrl);

如何使用Retrofit2下载文件？

UPDATE：

3 个答案: