我需要使用代理从 Azure blob 存储容器获取图像并将图像保存到 BufferedImage。
System.out.println("********Initiated******");
//Set Proxy Host name and Port
Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress("xx-xx-xxxxx", 8080));
OperationContext op = new OperationContext();
op.setProxy(proxy);
// Retrieve storage account from connection-string.
CloudStorageAccount storageAccount = CloudStorageAccount.parse(storageConnectionString);
// Create the blob client.
CloudBlobClient blobClient = storageAccount.createCloudBlobClient();
// Get a reference to a container.
// The container name must be lower case
CloudBlobContainer container = blobClient.getContainerReference("images");
//call via this overload
Iterable<ListBlobItem> blobs = container.listBlobs(null, false, EnumSet.noneOf(BlobListingDetails.class), new BlobRequestOptions(), op);
URL urlOfImage = null;
//Listing contents of container
for(ListBlobItem blob: blobs) {
/*Process the Image. Sample URL from Azure: **https://someWebsite.blob.core.windows.net/images/00001.png***/
if(((CloudBlockBlob) blob).getName().toLowerCase().contains(".png")) {
urlOfImage = blob.getUri().toURL();
BufferedImage buffimage = ImageIO.read(urlOfImage);
}
}
System.out.println("********Success*********");
通过使用 URI,我可以通过浏览器打开图像(单独)。
问题:我想直接或通过 URI 处理 blob 内容。如果我在将图像保存到缓冲图像时运行上面的代码, 我收到以下错误。
Exception in thread "main" javax.imageio.IIOException: Can't get input stream from URL!
at javax.imageio.ImageIO.read(Unknown Source)
提前致谢。
最佳答案
根据我的经验,您的问题是由没有 SAS token 的 blob url 导致的,无法直接访问。
这是我使用 SAS token 生成 blob url 的示例代码。
String connectionString = "<your storage connection string>"
String containerName = "<your container name>";
String blobName = "<your blob name>";
CloudStorageAccount account = CloudStorageAccount.parse(connectionString);
CloudBlobClient client = account.createCloudBlobClient();
CloudBlobContainer container = client.getContainerReference(containerName);
CloudBlockBlob blob = container.getBlockBlobReference(blobName);
SharedAccessBlobPolicy policy = new SharedAccessBlobPolicy();
policy.setPermissions(EnumSet.allOf(SharedAccessBlobPermissions.class));
policy.setSharedAccessStartTime(Date.valueOf(LocalDate.now().minusYears(2)));
policy.setSharedAccessExpiryTime(Date.valueOf(LocalDate.now().plusYears(2)));
String sas = blob.generateSharedAccessSignature(policy, null);
String urlWithSas = String.format("%s?%s", blob.getUri(), sas);
然后,您可以将 urlWithSas
值传递给不带代理的 ImageIO.read
方法来获取其 BufferedImage
对象,如下所示。
URL urlOfImage = new URL(urlWithSas);
BufferedImage buffimage = ImageIO.read(urlOfImage );
System.out.println(buffimage.getHeight());
这对我有用。
使用代理只需按照JDK官方文档Java Networking and Proxies
即可首先使用 System.setProperty
方法启用 JVM 代理联网。
System.setProperty("http.proxyHost", "<your proxy host>");
System.setProperty("http.proxyPort", "<your proxy port>");
<小时/>
更新:
下面代码的结果与上面相同。
HttpURLConnection conn = (HttpURLConnection) urlOfImage.openConnection();
conn.connect();
InputStream input = conn.getInputStream();
BufferedImage buffimage = ImageIO.read(input);
关于java - 使用 Java 中的代理从 Azure Blob 获取图像,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/55863696/