.NET-SDK之如何实现下载文件（二）?

只获取文件元信息


通过GetObjectMetadata方法可以只获取ObjectMeta而不获取文件的实体。代码如下：

1. // 初始化OssClient
2. var client = new OssClient(endpoint, accessKeyId, accessKeySecret);
4. /// <summary>
5. /// 获取文件的元信息。
6. /// </summary>
7. /// <param name="bucketName">存储空间的名称</param>
8. /// <param name="key">文件在OSS上的名称</param>
9. public void GetObjectMetadata(string bucketName, string key)
10. {
11.     try
12.     {
13.         var metadata = client.GetObjectMetadata(bucketName, key);
15.         Console.WriteLine("Get object meta succeeded");  
16.         Console.WriteLine("Content-Type:{0}", metadata.ContentType);
17.         Console.WriteLine("Cache-Control:{0}", metadata.CacheControl);
18.     }
19.     catch (Exception ex)
20.     {
21.         Console.WriteLine("Get object meta failed. {0}", ex.Message);
22.     }
23. }

1. using Aliyun.OSS;
3. var client = new OssClient(endpoint, accessKeyId, accessKeySecret);
5. public static void GetObjectProgress(string bucketName)
6. {
7.     const string key = "GetObjectProgress";
8.     try
9.     {
10.         client.PutObject(bucketName, key, fileToUpload);
12.         var getObjectRequest = new GetObjectRequest(bucketName, key);
13.         getObjectRequest.StreamTransferProgress += streamProgressCallback;
14.         var ossObject = client.GetObject(getObjectRequest);
15.         using (var stream = ossObject.Content)
16.         {
17.             var buffer = new byte[1024 * 1024];
18.             var bytesRead = 0;
19.             while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) > 0)
20.             {
21.                 // 处理读出的数据
22.             }                    
23.         }
25.         Console.WriteLine("Get object:{0} succeeded", key);
26.     }
27.     catch (OssException ex)
28.     {
29.         Console.WriteLine("Failed with error code: {0}; Error info: {1}. \nRequestID:{2}\tHostID:{3}",
30.             ex.ErrorCode, ex.Message, ex.RequestId, ex.HostId);
31.     }
32.     catch (Exception ex)
33.     {
34.         Console.WriteLine("Failed with error info: {0}", ex.Message);
35.     }
36. }
38. private static void streamProgressCallback(object sender, StreamTransferProgressArgs args)
39. {
40.     System.Console.WriteLine("ProgressCallback - TotalBytes:{0}, TransferredBytes:{1}",
41.         args.TotalBytes, args.TransferredBytes);
42. }

提示：

• PutObject、AppendObject、UploadPart、ResumableUploadObject、GetObject都支持进度功能，完整代码请参考：GitHub。