在 Android - Java 中寻找 InputStream

Question

我有一个文件传输应用程序，可以通过套接字连接将大文件（几 GB 大小）从 Android 发送到 Windows。我正在使用内容解析器将输入流实例获取到存储在 phone 中的文件，但我希望能够在输入流上来回搜索以使文件传输通过数据报通道更高效。有办法吗？

int ack, len;

Context context = getApplicationContext();
ContentResolver cr = context.getContentResolver();
InputStream is = cr.openInputStream(fileUri);

while ((len = is.read(bufr, 0, BUFFER_SIZE)) > 0) {
        ack = sendDatagramPacket(bufr, 0, len);
}

Answer 1

这是一种对我有用的值得尝试的方法。这个想法是通过获取 AssetFileDescriptor 将 InputStream 转换为 FileInputStream，然后获取一个 FileChannel 实例，让您来回搜索。

long position = 0, bytesRead = 0, currentRead = 0;

Context context = getApplicationContext();
ContentResolver cr = context.getContentResolver();
InputStream is = cr.openInputStream(fileUri);
AssetFileDescriptor assetFileDescriptor = null;
FileInputStream fis = null;
FileChannel fc = null;

        try {
            assetFileDescriptor = getContentResolver().openAssetFileDescriptor(fileUri[0], "r");
            is = cr.openInputStream(fileUri[0]);
            Utility.sendFileInfo(is, out, fileName);

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

        fis = new FileInputStream(assetFileDescriptor.getFileDescriptor());;
        fc = fis.getChannel();
        ByteBuffer buffer = ByteBuffer.allocate(Utility.BUFFER_SIZE);

        while(position < filesize){
            try {
                fc.position(position);
                currentRead = fc.read(buffer);

                //Use the populated buffer to send data out
                SendDatagramPacket(buffer, 0, currentRead)
                bytesRead += currentRead;
                position = bytesRead;
                buffer = ByteBuffer.allocate(Utility.BUFFER_SIZE);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

在 Android - Java 中寻找 InputStream

Seeking on an InputStream in Android - Java

java

android

socket.io

inputstream