读取失败：从 InputStream Nougat 读取时 EBADF（错误的文件描述符）答案

【问题标题】：read failed: EBADF (Bad file descriptor) while reading from InputStream Nougat读取失败：从 InputStream Nougat 读取时 EBADF（错误的文件描述符）
【发布时间】：2017-06-13 19:37:05
【问题描述】：

随着 android N 最近的变化，我不得不升级我的代码以使用 FileProvider 来使用相机/文件管理器获取图像/文件。该代码在模拟器（genymotion）中运行良好，但在 Moto G4 plus 中引发 IO 异常。

if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.N){
                try {
                    ParcelFileDescriptor fcd = getContentResolver().openFileDescriptor(uriOrig,"r");// uriOrig is the uri returned from camera
                    if(fcd != null) {
                        InputStream inputStream = new FileInputStream(fcd.getFileDescriptor());
                        uploadCall =RestService.getInstance().uploadFile(mimeType, name, size,
                                inputStream, defaultResponseCallback);
                    }

                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                }
            }

这里是上传文件的方法。

public Call<Attachment> uploadFile(final String mimeType, final String name, final long length,final InputStream is, final Callback<Attachment> callback) {
final int byteCount = 8192;
    if (length > 0) {
        RequestBody fileBody = new RequestBody() {

            @Override
            public MediaType contentType() {
                return !TextUtils.isEmpty(mimeType) ? MediaType.parse(mimeType) : null;
            }

            @Override
            public long contentLength() throws IOException {
                return length;
            }

            @Override
            public void writeTo(BufferedSink sink) throws IOException {
                final long fileLength = contentLength();
                byte[] buffer = new byte[byteCount];
                long uploaded = 0;

                try {
                    final Handler handler = new Handler(Looper.getMainLooper(), new Handler.Callback() {

                        @Override
                        public boolean handleMessage(Message msg) {
                            if (callback instanceof Callback2) {
                                Callback2 callback2 = (Callback2) callback;
                                long uploaded = (long) msg.obj;
                                callback2.onProgress(uploaded, fileLength);
                            }

                            return true;
                        }
                    });

                    int read;
                    while ((read = is.read(buffer)) != -1) {
                        uploaded += read;
                        sink.write(buffer, 0, read);
                        Log.d("write: ", "bytes: "+ new String(buffer));
                        Log.e("writeTo: ", uploaded + " up fd->");
                        // update progress on UI thread
                        handler.sendMessage(handler.obtainMessage(0, uploaded));
                    }

                    is.close();
                } catch (IOException e) {
                    Log.e("file_upload", "Exception thrown while uploading", e);
                }
                Log.e("sink: "+uploaded + " bytes ", sink.toString(), new Exception("check"));
            }
        };

        String fileName = name;
        int index = name.lastIndexOf(".");
        if (index < 0) {
            String extension = MimeTypeMap.getSingleton().getExtensionFromMimeType(mimeType);
            fileName += "." + extension;
        }

        MultipartBody.Part part = MultipartBody.Part.createFormData("file", fileName, fileBody);
        Call<Attachment> call = companyRestInterface.uploadFile(part);
        call.enqueue(callback);
        return call;
    }
}

堆栈跟踪

java.io.IOException: read failed: EBADF (Bad file descriptor)
                                                          at libcore.io.IoBridge.read(IoBridge.java:481)
                                                          at java.io.FileInputStream.read(FileInputStream.java:252)
                                                          at java.io.FileInputStream.read(FileInputStream.java:223)
                                                          at xend.app.http.RestService$10.writeTo(RestService.java:767)
                                                          at okhttp3.MultipartBody.writeOrCountBytes(MultipartBody.java:173)
                                                          at okhttp3.MultipartBody.writeTo(MultipartBody.java:114)
                                                          at okhttp3.internal.http.CallServerInterceptor.intercept(CallServerInterceptor.java:62)
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
                                                          at okhttp3.internal.connection.ConnectInterceptor.intercept(ConnectInterceptor.java:45)
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
                                                          at okhttp3.internal.cache.CacheInterceptor.intercept(CacheInterceptor.java:93)
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
                                                          at okhttp3.internal.http.BridgeInterceptor.intercept(BridgeInterceptor.java:93)
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
                                                          at okhttp3.internal.http.RetryAndFollowUpInterceptor.intercept(RetryAndFollowUpInterceptor.java:120)
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
                                                          at xend.app.http.MyInterceptor.intercept(MyInterceptor.java:51)
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
                                                          at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.java:185)
                                                          at okhttp3.RealCall$AsyncCall.execute(RealCall.java:135)
                                                          at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:32)
                                                          at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
                                                          at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
                                                          at java.lang.Thread.run(Thread.java:761)
                                                       Caused by: android.system.ErrnoException: read failed: EBADF (Bad file descriptor)
                                                          at libcore.io.Posix.readBytes(Native Method)
                                                          at libcore.io.Posix.read(Posix.java:169)
                                                          at libcore.io.BlockGuardOs.read(BlockGuardOs.java:231)
                                                          at libcore.io.IoBridge.read(IoBridge.java:471)
                                                          at java.io.FileInputStream.read(FileInputStream.java:252) 
                                                          at java.io.FileInputStream.read(FileInputStream.java:223) 
                                                          at xend.app.http.RestService$10.writeTo(RestService.java:767) 
                                                          at okhttp3.MultipartBody.writeOrCountBytes(MultipartBody.java:173) 
                                                          at okhttp3.MultipartBody.writeTo(MultipartBody.java:114) 
                                                          at okhttp3.internal.http.CallServerInterceptor.intercept(CallServerInterceptor.java:62) 
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92) 
                                                          at okhttp3.internal.connection.ConnectInterceptor.intercept(ConnectInterceptor.java:45) 
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92) 
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67) 
                                                          at okhttp3.internal.cache.CacheInterceptor.intercept(CacheInterceptor.java:93) 
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92) 
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67) 
                                                          at okhttp3.internal.http.BridgeInterceptor.intercept(BridgeInterceptor.java:93) 
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92) 
                                                          at okhttp3.internal.http.RetryAndFollowUpInterceptor.intercept(RetryAndFollowUpInterceptor.java:120) 
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92) 
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67) 
                                                          at xend.app.http.MyInterceptor.intercept(MyInterceptor.java:51) 
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92) 
                                                          at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67) 
                                                          at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.java:185) 
                                                          at okhttp3.RealCall$AsyncCall.execute(RealCall.java:135) 
                                                          at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:32) 
                                                          at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133) 
                                                          at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607) 
                                                          at java.lang.Thread.run(Thread.java:761)

非常感谢任何帮助。

编辑

图片 uri 部分。

Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
            File externalCacheDir = getExternalCacheDir();
File extFile = new File(externalCacheDir,
                        String.valueOf(System.currentTimeMillis()) + ".jpg");
mImageCaptureUri = FileProvider.getUriForFile(DirectChatActivity.this,
                            BuildConfig.APPLICATION_ID + ".provider",extFile);
                    grantUriPermission("xend.app", mImageCaptureUri, Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
                    cameraIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
                    cameraIntent.setFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, mImageCaptureUri);

这个 mImageCaptureUri 后来被称为 uriOrig。已获得所有权限并进行了相应的工作。

【问题讨论】：

这是从公共存储还是私有存储中提取数据？你有足够的权限吗？
uriOrig is the uri returned from camera -- 相机不返回 Uri 值。请显示uriOrig 的来源。
@MeetTitan，我已经编辑了问题以添加 uri 部分。抱歉，可能是我之前没有描述。
@CommonsWare 我已经按照建议获得了所有权限。部分文件正在上传，然后它突然停止并出现错误。
“这个 mImageCaptureUri 后来被称为 uriOrig”——我不知道怎么做。此外，只保留extFile 并使用直接文件 I/O 会更简单、更快捷。

标签： android retrofit2 multipart okhttp3 android-fileprovider

【解决方案1】：

问题在于 ParcelFileDescriptor。它关闭输入流。所以换行

ParcelFileDescriptor fcd = getContentResolver().openFileDescriptor(uriOrig,"r");// uriOrig is the uri returned from camera
                    if(fcd != null) {
                        InputStream inputStream = new FileInputStream(fcd.getFileDescriptor());
                        uploadCall =RestService.getInstance().uploadFile(mimeType, name, size,
                                inputStream, defaultResponseCallback);
                    }

与

InputStream inputStream = getContentResolver().openInputStream(uriOrig);
uploadCall =RestService.getInstance().uploadFile(mimeType, name, size,
                                inputStream, defaultResponseCallback);

完成了工作。

【讨论】：

同样适用于OutputStream。
您能否提供确认ParcelFileDescriptor 关闭流的来源？我正在尝试使用它来避免一遍又一遍地查询InputStream。

【解决方案2】：

我在写入和读取不同文件时遇到了类似的问题，我关闭了：文件输入/输出通道和文件输入/输出流但我忘了最后关闭关联的资产/包裹文件描述符。一旦我在最后关闭了资产/包裹文件描述符，这些随机的“坏文件描述符”异常就消失了。

【讨论】：

您好，可以分享一下代码吗？

【解决方案3】：

ParcelFileDescriptor 在范围结束之前已经完成，它关闭了流。使用ParcelFileDescriptor.AutoCloseInputStream 将解决您的问题，它拥有ParcelFileDescriptor 的强引用。

【讨论】：

嗨，Naden，请务必将代码 sn-p 与您的答案一起发布，以便开发人员发现您的答案更重要。
@Neden 你能分享一些代码吗

【解决方案4】：

在将文件下载到外部存储时更新 UI 进度条的频率超过了要求，这让我很受打击。我通过在计时器基础上更新进度并且仅增加 1% 来放松我的下载线程 (asyncTask) 中的 UI 更新。

【讨论】：