【Azure Developer】VS Code運作Java 版Azure Storage SDK操作Blob (建立Container, 上傳Blob檔案，下載下傳及清理)

VS Code運作Java 版Azure Storage SDK操作Blob (建立Container, 上傳Blob檔案，下載下傳及清理)

問題描述

是否可以用Java代碼來管理Azure blob？ 可以。在代碼中加入azure-storage-blob依賴。即可使用以下類操作Azure Storage Blob。

• BlobServiceClient：BlobServiceClient 類可用于操縱 Azure 存儲資源和 blob 容器。 存儲帳戶為 Blob 服務提供頂級命名空間。
• BlobServiceClientBuilder：BlobServiceClientBuilder 類提供流暢的生成器 API，以幫助對 BlobServiceClient 對象的配置和執行個體化。
• BlobContainerClient：BlobContainerClient 類可用于操縱 Azure 存儲容器及其 blob。
• BlobClient：BlobClient 類可用于操縱 Azure 存儲 blob。
• BlobItem：BlobItem 類表示從對 listBlobs 的調用傳回的單個 blob。

執行步驟

首先，設定VS Code上執行Java 代碼的環境，這裡需要的步驟比較多。完全參考VS Code for Java文檔即可：https://code.visualstudio.com/docs/java/java-tutorial. 

以下是建立項目步驟：

1）建立blob-quickstart-v12項目

跳轉到blob-quickstart-v12目錄，并在目錄中建立一個data目錄，用于在接下來的代碼中建立本地檔案及下載下傳bolb中的檔案

cd blob-quickstart-v12

mkdir data      

2)   修改pom.xml，添加對Java azure-storage-blob SDK的依賴

<dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>com.azure</groupId>
      <artifactId>azure-storage-blob</artifactId>
      <version>12.6.0</version>
  </dependency>
  </dependencies>      

3）在App.java代碼檔案中添加引用

package com.blobs.quickstart;

/**
 * Azure blob storage v12 SDK quickstart
 */
import com.azure.storage.blob.*;
import com.azure.storage.blob.models.*;
import java.io.*;

public class App
{
    public static void main( String[] args ) throws IOException
    {
        System.out.println("Azure Blob storage v12 - Java quickstart sample\n");      

4）添加Stroage Account的連接配接字元串

5）建立blobServiceClient對象，同時調用createBlobContainer方法建立容器

// Create a BlobServiceClient object which will be used to create a container client
        BlobServiceClient blobServiceClient = new BlobServiceClientBuilder().connectionString(connectStr).buildClient();

        //Create a unique name for the container
        String containerName = "quickstartblobs" + java.util.UUID.randomUUID();

        // Create the container and return a container client object
        BlobContainerClient containerClient = blobServiceClient.createBlobContainer(containerName);      

6）建立BlobClient對象，同時調用uploadFromFile方法上傳檔案(.tx)

// Create a local file in the ./data/ directory for uploading and downloading
        String localPath = "./data/";
        String fileName = "quickstart" + java.util.UUID.randomUUID() + ".txt";
        File localFile = new File(localPath + fileName);

        // Write text to the file
        FileWriter writer = new FileWriter(localPath + fileName, true);
        writer.write("Hello, World!");
        writer.close();

        // Get a reference to a blob
        BlobClient blobClient = containerClient.getBlobClient(fileName);

        System.out.println("\nUploading to Blob storage as blob:\n\t" + blobClient.getBlobUrl());

        // Upload the blob
        blobClient.uploadFromFile(localPath + fileName);      

7）使用containerClient對象的listBlobs方法列出容器中的BlobItem

System.out.println("\nListing blobs...");

        // List the blob(s) in the container.
        for (BlobItem blobItem : containerClient.listBlobs()) {
            System.out.println("\t" + blobItem.getName());
        }      

8）使用blobClient對象的downloadToFile方法下載下傳檔案到本地

// Download the blob to a local file
        // Append the string "DOWNLOAD" before the .txt extension so that you can see both files.
        String downloadFileName = fileName.replace(".txt", "DOWNLOAD.txt");
        File downloadedFile = new File(localPath + downloadFileName);

        System.out.println("\nDownloading blob to\n\t " + localPath + downloadFileName);

        blobClient.downloadToFile(localPath + downloadFileName);      

9）使用containerClient對象的delete方法删除容器

// Clean up
        System.out.println("\nPress the Enter key to begin clean up");
        System.console().readLine();

        System.out.println("Deleting blob container...");
        containerClient.delete();

        System.out.println("Deleting the local source and downloaded files...");
        localFile.delete();
        downloadedFile.delete();

        System.out.println("Done");      

10） 在VS Code中調試或執行，右鍵選擇Run/Debug

全部代碼

App.java檔案

package com.blobs.quickstart;

/**
 * Azure blob storage v12 SDK quickstart
 */
import com.azure.storage.blob.*;
import com.azure.storage.blob.models.*;
import java.io.*;

public class App
{
    public static void main( String[] args ) throws IOException
    {
        System.out.println("Azure Blob storage v12 - Java quickstart sample\n");

        // Retrieve the connection string for use with the application. The storage
        // connection string is stored in an environment variable on the machine
        // running the application called AZURE_STORAGE_CONNECTION_STRING. If the environment variable
        // is created after the application is launched in a console or with
        // Visual Studio, the shell or application needs to be closed and reloaded
        // to take the environment variable into account.
        String connectStr ="DefaultEndpointsProtocol=https;AccountName=xxxxxxxx;AccountKey=xxxxxxxxxxxxxxx;EndpointSuffix=core.chinacloudapi.cn";// System.getenv("AZURE_STORAGE_CONNECTION_STRING");

        // Create a BlobServiceClient object which will be used to create a container client
        BlobServiceClient blobServiceClient = new BlobServiceClientBuilder().connectionString(connectStr).buildClient();

        //Create a unique name for the container
        String containerName = "quickstartblobs" + java.util.UUID.randomUUID();

        // Create the container and return a container client object
        BlobContainerClient containerClient = blobServiceClient.createBlobContainer(containerName);

        // Create a local file in the ./data/ directory for uploading and downloading
        String localPath = "./data/";
        String fileName = "quickstart" + java.util.UUID.randomUUID() + ".txt";
        File localFile = new File(localPath + fileName);

        // Write text to the file
        FileWriter writer = new FileWriter(localPath + fileName, true);
        writer.write("Hello, World!");
        writer.close();

        // Get a reference to a blob
        BlobClient blobClient = containerClient.getBlobClient(fileName);

        System.out.println("\nUploading to Blob storage as blob:\n\t" + blobClient.getBlobUrl());

        // Upload the blob
        blobClient.uploadFromFile(localPath + fileName);

        System.out.println("\nListing blobs...");

        // List the blob(s) in the container.
        for (BlobItem blobItem : containerClient.listBlobs()) {
            System.out.println("\t" + blobItem.getName());
        }

        // Download the blob to a local file
        // Append the string "DOWNLOAD" before the .txt extension so that you can see both files.
        String downloadFileName = fileName.replace(".txt", "DOWNLOAD.txt");
        File downloadedFile = new File(localPath + downloadFileName);

        System.out.println("\nDownloading blob to\n\t " + localPath + downloadFileName);

        blobClient.downloadToFile(localPath + downloadFileName);

        // Clean up
        System.out.println("\nPress the Enter key to begin clean up");
        System.console().readLine();

        System.out.println("Deleting blob container...");
        containerClient.delete();

        System.out.println("Deleting the local source and downloaded files...");
        localFile.delete();
        downloadedFile.delete();

        System.out.println("Done");
    }
}      

pom.xml檔案

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.blobs.quickstart</groupId>
  <artifactId>blob-quickstart-v12</artifactId>
  <version>1.0-SNAPSHOT</version>

  <name>blob-quickstart-v12</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>com.azure</groupId>
      <artifactId>azure-storage-blob</artifactId>
      <version>12.6.0</version>
  </dependency>
  </dependencies>

  <build>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-jar-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
        <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
        <plugin>
          <artifactId>maven-site-plugin</artifactId>
          <version>3.7.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-project-info-reports-plugin</artifactId>
          <version>3.0.0</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>      

參考資料

Getting Started with Java in VS Code：https://code.visualstudio.com/docs/java/java-tutorial

快速入門：使用 Java v12 SDK 管理 blob: https://docs.azure.cn/zh-cn/storage/blobs/storage-quickstart-blobs-java#code-examples

當在複雜的環境中面臨問題，格物之道需：濁而靜之徐清，安以動之徐生。 雲中，恰是如此!