Question

我在android中使用okhttp库下载文件。我下载成功了。但是当我暂停并恢复下载时出现问题。

Response request = new Request.Builder().url(url).build();
ResponseBody responseBody = response.body();

File file = new File(filePath);
BufferedInputStream input = new BufferedInputStream(responseBody.byteStream());
OutputStream output;

if (isResume) {
    output = new FileOutputStream(file, true);
    input.skip(downloadedSize);
} else {
    output = new FileOutputStream(file, false);    
}

long totalByteSize = responseBody.contentLength();
byte[] data = new byte[1024];
int count = 0;

while ((count = input.read(data)) != -1) {
    downloadedSize += count;
    output.write(data, 0, count);   
}

问题是例如文件大小是10MB。下载3MB然后恢复下载时暂停，下载完成后文件大小变成13MB。它不是从恢复时的下载大小开始，它从字节流开始下载。所以文件变成13MB。代码有什么问题？

Answer 1

第一天

我尝试了很多代码，最后用 BufferedSource source = responseBody.source（）解决了问题。 source.skip（downloadedSize）;

Response request = new Request.Builder().url(url).build(); ResponseBody responseBody = response.body(); BufferedSource source = responseBody.source(); if(isResume) source.skip(downloadedSize); File file = new File(filePath); BufferedInputStream input = new BufferedInputStream(responseBody.byteStream()); OutputStream output; if (isResume) { output = new FileOutputStream(file, true); } else { output = new FileOutputStream(file, false); } long currentDownloadedSize = 0; long currentTotalByteSize = responseBody.contentLength(); byte[] data = new byte[1024]; int count = 0; while ((count = input.read(data)) != -1) { currentDownloadedSize += count; output.write(data, 0, count); }

它运作成功。我想我很幸运:)）

第二种方式

我为跳过下载的字节添加了标题并且它有效。

Request.Builder requestBuilder = new Request.Builder(); if (isResume) { requestBuilder.addHeader("Range", "bytes=" + String.valueOf(downloadedSize) + "-"); } Response request = requestBuilder.url(url).build(); ResponseBody responseBody = response.body(); BufferedSource source = responseBody.source(); File file = new File(filePath); BufferedInputStream input = new BufferedInputStream(responseBody.byteStream()); OutputStream output; if (isResume) { output = new FileOutputStream(file, true); } else { output = new FileOutputStream(file, false); } long currentDownloadedSize = 0; long currentTotalByteSize = responseBody.contentLength(); byte[] data = new byte[1024]; int count = 0; while ((count = input.read(data)) != -1) { currentDownloadedSize += count; output.write(data, 0, count); }

Answer 2

val call = client.newCall(request)

call.enqueue(object : Callback {
    override fun onFailure(call: Call, e: IOException) {
        listener.onFail(e)
    }

    override fun onResponse(call: Call, response: Response) {
        // write the stream to a file (downloading happening)
        val stream = response.body?.byteStream()
    }
})

// this will stop the downloading
call.cancel()

要继续使用请求中的“ Range”标头，并将流附加到已下载的文件中。

如何在Android中使用okhttp暂停/继续下载

2 个答案: