仅当在 while 循环中调用函数时，将文件发送到 blob 才有效

Posted 2023-03-28

【中文标题】仅当在 while 循环中调用函数时，将文件发送到 blob 才有效

【英文标题】：Sending file to blob only works when function is called in while loop

【发布时间】：2019-11-22 11:18:22

【问题描述】：

我有正在尝试修改的 Azure blob 示例代码。但是，uploadFile 函数仅在 switch 情况下的 while 循环中有效。如果我将它从循环中取出，它会创建容器但无法上传文件。

我尝试将其取出并从代码中的不同位置调用该函数，但它们都不起作用。

上传文件功能：

 static void uploadFile(BlockBlobURL blob, File sourceFile) throws IOException 

        AsynchronousFileChannel fileChannel = AsynchronousFileChannel.open(sourceFile.toPath());

        // Uploading a file to the blobURL using the high-level methods available in TransferManager class
        // Alternatively call the PutBlob/PutBlock low-level methods from BlockBlobURL type
        TransferManager.uploadFileToBlockBlob(fileChannel, blob, 8*1024*1024, null, null)
                .subscribe(response-> 
                    System.out.println("Completed upload request.");
                    TimeUnit.SECONDS.sleep(5);
                    System.out.println(response.response().statusCode());
                );


    

main的相关部分

            // Listening for commands from the console
            //THIS IS THE PART THAT ONLY MAKES THE CONTAINER
            /*
            System.out.println("Uploading the sample file into the container: " + containerURL );
            uploadFile(blobURL, sampleFile);
            System.out.println("File Uploaded");
            */
            //TRYING TO CALL FUNCTION FROM OUTSIDE WHILE, BUT IT ONLY WORKS HERE
            System.out.println("Enter a command");
            System.out.println("(P)utBlob | (L)istBlobs | (G)etBlob");
            BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
            while (true) 
                System.out.println("# Enter a command : ");
                String input = reader.readLine();
                switch(input)
                    case "P":
                        System.out.println("Uploading the sample file into the container: " + containerURL );
                        uploadFile(blobURL, sampleFile);
                        break;

在 while 循环之外调用的 uploadFile 会创建容器，但实际上不会将文件上传到 blob，而在 while 循环和 switch case 中调用的 uploadFile 会

【问题讨论】：

是的，现在可以使用了。感谢您的帮助

【参考方案1】：

这不会上传 blob，因为上传过程尚未完成且主过程已完成。所以我只是在主进程中添加一个Thread.sleep()。并且提醒不要将值设置得太短，否则仍然会失败。在我的测试中，我将其设置为 2000 毫秒。

public static void main(String[] args) throws java.lang.Exception


        ContainerURL containerURL;

        // Creating a sample file to use in the sample
        File sampleFile = null;

        try 
            sampleFile = File.createTempFile("downloadedFile", ".txt");

            // Retrieve the credentials and initialize SharedKeyCredentials
            String accountName = "xxxxxx";
            String accountKey = "xxxxxxx";

            // Create a ServiceURL to call the Blob service. We will also use this to construct the ContainerURL
            SharedKeyCredentials creds = new SharedKeyCredentials(accountName, accountKey);
            // We are using a default pipeline here, you can learn more about it at https://github.com/Azure/azure-storage-java/wiki/Azure-Storage-Java-V10-Overview
            final ServiceURL serviceURL = new ServiceURL(new URL("https://" + accountName + ".blob.core.windows.net"), StorageURL.createPipeline(creds, new PipelineOptions()));

            // Let's create a container using a blocking call to Azure Storage
            // If container exists, we'll catch and continue
            containerURL = serviceURL.createContainerURL("quickstart");

            try 
                ContainerCreateResponse response = containerURL.create(null, null, null).blockingGet();
                System.out.println("Container Create Response was " + response.statusCode());
             catch (RestException e)
                if (e instanceof RestException && ((RestException)e).response().statusCode() != 409) 
                    throw e;
                 else 
                    System.out.println("quickstart container already exists, resuming...");
                
            

            // Create a BlockBlobURL to run operations on Blobs
            final BlockBlobURL blobURL = containerURL.createBlockBlobURL("SampleBlob.txt");

            System.out.println("Uploading the sample file into the container: " + containerURL );
            AsynchronousFileChannel fileChannel = AsynchronousFileChannel.open(sampleFile.toPath());


            // Uploading a file to the blobURL using the high-level methods available in TransferManager class
            // Alternatively call the PutBlob/PutBlock low-level methods from BlockBlobURL type
            TransferManager.uploadFileToBlockBlob(fileChannel, blobURL, 8*1024*1024, null, null)
                    .subscribe(response-> 
                        System.out.println("Completed upload request.");
                        System.out.println(response.response().statusCode());
                    );

            Thread.sleep(2000);

         catch (InvalidKeyException e) 
            System.out.println("Invalid Storage account name/key provided");
         catch (MalformedURLException e) 
            System.out.println("Invalid URI provided");
         catch (RestException e)
            System.out.println("Service error returned: " + e.response().statusCode() );
         catch (IOException e) 
            e.printStackTrace();
            System.exit(-1);