如果要下载的文件太大，或者一次性下载耗时太长，您可以通过流式下载，一次处理部分内容，直到完成文件的下载。

下载指定文件后将获得文件的输入流，此操作要求用户对该Object有读权限。

同步调用：

//构造下载文件请求
GetObjectRequest get = new GetObjectRequest("<bucketName>", "<objectKey>");

//设置下载进度回调
get.setProgressListener(new OSSProgressCallback<GetObjectRequest>() {
            @Override
            public void onProgress(GetObjectRequest request, long currentSize, long totalSize) {
                OSSLog.logDebug("getobj_progress: " + currentSize+"  total_size: " + totalSize, false);
            }
        });

try {
	// 同步执行下载请求，返回结果
	GetObjectResult getResult = oss.getObject(get);

	Log.d("Content-Length", "" + getResult.getContentLength());

	// 获取文件输入流
	InputStream inputStream = getResult.getObjectContent();

	byte[] buffer = new byte[2048];
	int len;

	while ((len = inputStream.read(buffer)) != -1) {
		// 处理下载的数据，比如图片展示或者写入文件等
	}

	// 下载后可以查看文件元信息
	ObjectMetadata metadata = getResult.getMetadata();
	Log.d("ContentType", metadata.getContentType());


} catch (ClientException e) {
	// 本地异常如网络异常等
	e.printStackTrace();
} catch (ServiceException e) {
	// 服务异常
	Log.e("RequestId", e.getRequestId());
	Log.e("ErrorCode", e.getErrorCode());
	Log.e("HostId", e.getHostId());
	Log.e("RawMessage", e.getRawMessage());
} catch (IOException e) {
	e.printStackTrace();
}

异步调用：

GetObjectRequest get = new GetObjectRequest("<bucketName>", "<objectKey>");
//设置下载进度回调
get.setProgressListener(new OSSProgressCallback<GetObjectRequest>() {
            @Override
            public void onProgress(GetObjectRequest request, long currentSize, long totalSize) {
                OSSLog.logDebug("getobj_progress: " + currentSize+"  total_size: " + totalSize, false);
            }
        });
OSSAsyncTask task = oss.asyncGetObject(get, new OSSCompletedCallback<GetObjectRequest, GetObjectResult>() {
	@Override
	public void onSuccess(GetObjectRequest request, GetObjectResult result) {
		// 请求成功
		InputStream inputStream = result.getObjectContent();

		byte[] buffer = new byte[2048];
		int len;

		try {
			while ((len = inputStream.read(buffer)) != -1) {
				// 处理下载的数据
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	@Override
	public void onFailure(GetObjectRequest request, ClientException clientExcepion, ServiceException serviceException) {
		// 请求异常
		if (clientExcepion != null) {
			// 本地异常如网络异常等
			clientExcepion.printStackTrace();
		}
		if (serviceException != null) {
			// 服务异常
			Log.e("ErrorCode", serviceException.getErrorCode());
			Log.e("RequestId", serviceException.getRequestId());
			Log.e("HostId", serviceException.getHostId());
			Log.e("RawMessage", serviceException.getRawMessage());
		}
	}
});