【Azure Developer】VS Code运行Java 版Azure Storage SDK操作Blob (新建Container, 上传Blob文件，下载及清理)

问题描述

是否可以用Java代码来管理Azure blob？ 可以。在代码中加入azure-storage-blob依赖。即可使用以下类操作Azure Storage Blob。

• BlobServiceClient：BlobServiceClient 类可用于操纵 Azure 存储资源和 blob 容器。 存储帐户为 Blob 服务提供顶级命名空间。
• BlobServiceClientBuilder：BlobServiceClientBuilder 类提供流畅的生成器 API，以帮助对 BlobServiceClient 对象的配置和实例化。
• BlobContainerClient：BlobContainerClient 类可用于操纵 Azure 存储容器及其 blob。
• BlobClient：BlobClient 类可用于操纵 Azure 存储 blob。
• BlobItem：BlobItem 类表示从对 listBlobs 的调用返回的单个 blob。

执行步骤

首先，设置VS Code上执行Java 代码的环境，这里需要的步骤比较多。完全参考VS Code for Java文档即可：https://code.visualstudio.com/docs/java/java-tutorial. 

以下是创建项目步骤：

1）创建blob-quickstart-v12项目

跳转到blob-quickstart-v12目录，并在目录中创建一个data目录，用于在接下来的代码中创建本地文件及下载bolb中的文件

cd blob-quickstart-v12

mkdir data

2)   修改pom.xml，添加对Java azure-storage-blob SDK的依赖

  <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代码文件中添加引用

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
");

4）添加Stroage Account的连接字符串

5）创建blobServiceClient对象，同时调用createBlobContainer方法创建容器

        // 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）创建BlobClient对象，同时调用uploadFromFile方法上传文件(.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("
Uploading to Blob storage as blob:
	" + blobClient.getBlobUrl());

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

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

        System.out.println("
Listing blobs...");

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

8）使用blobClient对象的downloadToFile方法下载文件到本地

        // 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("
Downloading blob to
	 " + localPath + downloadFileName);

        blobClient.downloadToFile(localPath + downloadFileName);

9）使用containerClient对象的delete方法删除容器

        // Clean up
        System.out.println("
Press 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中调试或执行，右键选择Run/Debug

全部代码

App.java文件

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
");

        // 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("
Uploading to Blob storage as blob:
	" + blobClient.getBlobUrl());

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

        System.out.println("
Listing blobs...");

        // List the blob(s) in the container.
        for (BlobItem blobItem : containerClient.listBlobs()) {
            System.out.println("	" + 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("
Downloading blob to
	 " + localPath + downloadFileName);

        blobClient.downloadToFile(localPath + downloadFileName);

        // Clean up
        System.out.println("
Press 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文件

<?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>

参考资料

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

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