Question

我正在尝试下载mp4文件，但未能这样做。大小为25 MB的文件在目标文件夹中显示为~20 KB的文件。这是我的代码：

public class DownloadStream {

    private final String VIDEO_FOLDER = "StackoverflowQuestion";
    private String URL;
    private String title;
    Context context;
    File rootDirectory;

    public DownloadStream(String URL, String title, Context context) {
        this.URL = URL;
        this.title = title;
        this.context = context;
        File filepath = Environment.getExternalStorageDirectory();
        rootDirectory = new File(filepath, VIDEO_FOLDER);
        if (!rootDirectory.exists()) {
            rootDirectory.mkdir();
        }
        DownloadObservable()
                .observeOn(AndroidSchedulers.mainThread())
                .subscribeOn(Schedulers.io())
                .subscribe(new Subscriber<String>() {
                    @Override
                    public void onCompleted() {
                    }

                    @Override
                    public void onError(Throwable e) {

                    }

                    @Override
                    public void onNext(String s) {

                    }
                });
    }


    Observable<String> DownloadObservable(){
        return Observable.create(new Observable.OnSubscribe<String>() {
            @Override
            public void call(Subscriber<? super String> subscriber) {
                java.net.URL url;
                int contentLength;
                int counter = 0;
                int percentage;
                try {
                    url = new URL(URL);
                    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                    contentLength = connection.getContentLength();
                    connection.setRequestMethod("GET");
                    connection.connect();
                    File file = new File(rootDirectory, title + ".mp4");
                    InputStream inputStream = connection.getInputStream();
                    FileOutputStream fileOutputStream = new FileOutputStream(file);

                    byte buffer[] = new byte[1024];
                    int byteCount = 0;
                    while (inputStream.read(buffer) > 0) {
                        byteCount = inputStream.read(buffer);
                        fileOutputStream.write(buffer, 0, byteCount);
                        counter = byteCount + counter;
                        percentage = byteCount / contentLength;
                    }

                    fileOutputStream.close();
                    subscriber.onCompleted();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });
    }


}

我做错了什么？有没有更好的方法来做我想做的事情？

Answer 1

你读太多：

while (inputStream.read(buffer) > 0) { //Fill buffer once
    byteCount = inputStream.read(buffer); //fill buffer again

读取两次但只写了一次缓冲区。

以这种方式尝试：

int byteCount = inputStream.read(buffer);
while (byteCount >= 0) {
     fileOutputStream.write(buffer, 0, byteCount);
     counter = byteCount + counter;
     percentage = byteCount / contentLength;
     byteCount = inputStream.read(buffer);
}

无法下载mp4文件

1 个答案: