Android:上传视频时出现 OutOfMemoryError - 如何最好地分块？

Question

我有同样的问题 as described here ，但我会提供更多细节。尝试在 Android 中上传视频时，我正在将其读入内存，如果视频很大，我会收到 OutOfMemoryError。

这是我的代码:

// get bytestream to upload
videoByteArray = getBytesFromFile(cR, fileUriString);

public static byte[] getBytesFromFile(ContentResolver cR, String fileUriString) throws IOException {
    Uri tempuri = Uri.parse(fileUriString);
    InputStream is = cR.openInputStream(tempuri);
    byte[] b3 = readBytes(is);
    is.close();
    return b3;
}
public static byte[] readBytes(InputStream inputStream) throws IOException {
    ByteArrayOutputStream byteBuffer = new ByteArrayOutputStream();
    // this is storage overwritten on each iteration with bytes
    int bufferSize = 1024;
    byte[] buffer = new byte[bufferSize];
    int len = 0;
    while ((len = inputStream.read(buffer)) != -1) {
        byteBuffer.write(buffer, 0, len);
    }
    return byteBuffer.toByteArray();
}

这是回溯(错误在 byteBuffer.write(buffer, 0, len) 行上抛出):

04-08 11:56:20.456: ERROR/dalvikvm-heap(6088): Out of memory on a 16775184-byte allocation.
04-08 11:56:20.456: INFO/dalvikvm(6088): "IntentService[UploadService]" prio=5 tid=17 RUNNABLE
04-08 11:56:20.456: INFO/dalvikvm(6088):   | group="main" sCount=0 dsCount=0 s=N obj=0x449a3cf0 self=0x38d410
04-08 11:56:20.456: INFO/dalvikvm(6088):   | sysTid=6119 nice=0 sched=0/0 cgrp=default handle=4010416
04-08 11:56:20.456: INFO/dalvikvm(6088):   at java.io.ByteArrayOutputStream.expand(ByteArrayOutputStream.java:~93)
04-08 11:56:20.456: INFO/dalvikvm(6088):   at java.io.ByteArrayOutputStream.write(ByteArrayOutputStream.java:218)
04-08 11:56:20.456: INFO/dalvikvm(6088):   at com.android.election2010.UploadService.readBytes(UploadService.java:199)
04-08 11:56:20.456: INFO/dalvikvm(6088):   at com.android.election2010.UploadService.getBytesFromFile(UploadService.java:182)
04-08 11:56:20.456: INFO/dalvikvm(6088):   at com.android.election2010.UploadService.doUploadinBackground(UploadService.java:118)
04-08 11:56:20.456: INFO/dalvikvm(6088):   at com.android.election2010.UploadService.onHandleIntent(UploadService.java:85)
04-08 11:56:20.456: INFO/dalvikvm(6088):   at android.app.IntentService$ServiceHandler.handleMessage(IntentService.java:30)
04-08 11:56:20.456: INFO/dalvikvm(6088):   at android.os.Handler.dispatchMessage(Handler.java:99)
04-08 11:56:20.456: INFO/dalvikvm(6088):   at android.os.Looper.loop(Looper.java:123)
04-08 11:56:20.456: INFO/dalvikvm(6088):   at android.os.HandlerThread.run(HandlerThread.java:60)
04-08 11:56:20.467: WARN/dalvikvm(6088): threadid=17: thread exiting with uncaught exception (group=0x4001b180)
04-08 11:56:20.467: ERROR/AndroidRuntime(6088): Uncaught handler: thread IntentService[UploadService] exiting due to uncaught exception
04-08 11:56:20.467: ERROR/AndroidRuntime(6088): java.lang.OutOfMemoryError
04-08 11:56:20.467: ERROR/AndroidRuntime(6088):     at java.io.ByteArrayOutputStream.expand(ByteArrayOutputStream.java:93)
04-08 11:56:20.467: ERROR/AndroidRuntime(6088):     at java.io.ByteArrayOutputStream.write(ByteArrayOutputStream.java:218)
04-08 11:56:20.467: ERROR/AndroidRuntime(6088):     at com.android.election2010.UploadService.readBytes(UploadService.java:199)
04-08 11:56:20.467: ERROR/AndroidRuntime(6088):     at com.android.election2010.UploadService.getBytesFromFile(UploadService.java:182)
04-08 11:56:20.467: ERROR/AndroidRuntime(6088):     at com.android.election2010.UploadService.doUploadinBackground(UploadService.java:118)
04-08 11:56:20.467: ERROR/AndroidRuntime(6088):     at com.android.election2010.UploadService.onHandleIntent(UploadService.java:85)
04-08 11:56:20.467: ERROR/AndroidRuntime(6088):     at android.app.IntentService$ServiceHandler.handleMessage(IntentService.java:30)
04-08 11:56:20.467: ERROR/AndroidRuntime(6088):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-08 11:56:20.467: ERROR/AndroidRuntime(6088):     at android.os.Looper.loop(Looper.java:123)
04-08 11:56:20.467: ERROR/AndroidRuntime(6088):     at android.os.HandlerThread.run(HandlerThread.java:60)
04-08 11:56:20.496: INFO/Process(4657): Sending signal. PID: 6088 SIG: 3

我想 as @DroidIn suggests ，我需要分块上传。但是(新手问题警报)这是否意味着我应该发出多个 PostMethod 请求，并在服务器端将文件粘合在一起？或者我可以将字节流分块加载到内存中，然后在 Android 代码中将它们粘合在一起吗？

如果有人能给我提供有关最佳方法的线索，我将不胜感激。

Answer 1

Jim Blackler 是绝对正确的。你不能在 byte[] 的内存中有完整的视频。所以你应该读取文件而不是 byte[] 而是直接到 HttpUrlConnectio.getOutputStream()。

但即使在那之后你仍然会得到 OutOfMemory，因为 HttpUrlConnection 将所有输出数据缓存在内存中并仅在你完成写入时将其发送到网络。

要覆盖此行为，您可以使用 HttpUrlConnection.setChunkedStreamingMode() 或 HttpUrlConnection.setFixedLengthStreamingMode()。如果您的服务器接受流 block ，您可以使用 setChunkedStreamingMode()。否则，您将不得不使用 setFixedLengthStreamingMode。要使用 setFixedLengthStreamingMode，您需要在开始流式传输数据之前知道确切的内容长度，因此这有点棘手。

此时不再有 OutOfMemory。

如果您有视频文件，您可以选择另一种方法，更简单。像那样使用 HttpClient 和 FileBody How to send HTTP POST request and receive response? .我认为他们实现了上述所有方法，您不必为此担心。