阿里云对象存储OSS SDK的使用

官方文档

https://help.aliyun.com/zh/oss/developer-reference/java

准备工作

windows安装好JDK，这里使用JDK1.8为例
windows安装好IDEA，这里使用IDEA2022
登录阿里云控制台，通过免费试用OSS或开通OSS

步骤

配置访问凭证

有临时和长期访问凭证，简单起见，这里使用长期访问凭证。

配置RAM用户的访问密钥

1.创建RAM用户

登录阿里云，搜索访问控制，进入RAM 访问控制
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在RAM 访问控制中，创建RAM用户
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填写用户信息，勾选相关访问方式，点击确定

安全验证，根据提示进行其中一个验证。

得到RAM用户的相关信息，例如登录名称、登录密码、AccessKey ID和Access Secret

点击用户，找到刚创建的RAM用户一行，点击添加权限

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添加AliyunOSSFullAccess权限

2.配置RAM用户的访问密钥。

有两种方式配置RAM用户的访问密钥

设置环境变量
代码嵌入
把AccessKey ID和Access Secret设置在环境变量里比直接代码嵌入的方式更加安全些，两种方式选择其中之一即可。

设置环境变量

打开cmd命令行。

执行以下命令配置RAM用户的访问密钥。

set OSS_ACCESS_KEY_ID=LTAI4GDty8ab9W4Y1D****
set OSS_ACCESS_KEY_SECRET=IrVTNZNy5yQelTETg0cZML3TQn****

注意： OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET修改为对应AccessKey ID和Access Secret的值。
在这里插入图片描述

执行以下命令以使更改生效。

setx OSS_ACCESS_KEY_ID "%OSS_ACCESS_KEY_ID%"
setx OSS_ACCESS_KEY_SECRET "%OSS_ACCESS_KEY_SECRET%"

这个过程其实是往用户的环境变量里设置相应的值(用图形界面设置也一样)
在这里插入图片描述

执行以下命令验证环境变量配置。

echo %OSS_ACCESS_KEY_ID%
echo %OSS_ACCESS_KEY_SECRET%

成功返回示例如下：

LTAI4GDty8ab9W4Y1D****
IrVTNZNy5yQelTETg0cZML3TQn****

从环境变量中获取RAM用户的访问密钥。

// 使用环境变量中获取的RAM用户的访问密钥配置访问凭证。
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();

注意：设置环境变量后，如果之前已经打开IDEA，后面使用代码去获取环境变量时，需要重启IDEA，才能获取到新的环境变量设置。否则获取到的环境变量为null

代码嵌入

// RAM用户的访问密钥（AccessKey ID和AccessKey Secret）。
String accessKeyId = "yourAccessKeyId";
String accessKeySecret = "yourAccessKeySecret";
// 使用代码嵌入的RAM用户的访问密钥配置访问凭证。
CredentialsProvider credentialsProvider = new DefaultCredentialProvider(accessKeyId, accessKeySecret);

代码开发

1. 创建maven工程

打开IDEA->点击File->New Project
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2. 添加sdk依赖

    <dependencies><dependency><groupId>com.aliyun.oss</groupId><artifactId>aliyun-sdk-oss</artifactId><version>3.15.1</version></dependency></dependencies>

刷新依赖

3. 功能代码开发

使用SDK API实现创建Bucket、列举Bucket文件、上传文件、下载文件、删除文件。代码参考官方帮助文档。
代码结构如下：
在这里插入图片描述

创建Bucket

package org.example;import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.common.auth.CredentialsProviderFactory;
import com.aliyun.oss.common.auth.EnvironmentVariableCredentialsProvider;public class CreateBucketDemo {public static void main(String[] args) throws Exception {// Endpoint以华东1（杭州）为例，其它Region请按实际情况填写。String endpoint = "https://oss-cn-shenzhen.aliyuncs.com";// 从环境变量中获取访问凭证。运行本代码示例之前，请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();// 填写Bucket名称，例如examplebucket。String bucketName = "examplebucket-test-test900";// 创建OSSClient实例。OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);try {// 创建存储空间。ossClient.createBucket(bucketName);} catch (OSSException oe) {System.out.println("Caught an OSSException, which means your request made it to OSS, "+ "but was rejected with an error response for some reason.");System.out.println("Error Message:" + oe.getErrorMessage());System.out.println("Error Code:" + oe.getErrorCode());System.out.println("Request ID:" + oe.getRequestId());System.out.println("Host ID:" + oe.getHostId());} catch (ClientException ce) {System.out.println("Caught an ClientException, which means the client encountered "+ "a serious internal problem while trying to communicate with OSS, "+ "such as not being able to access the network.");System.out.println("Error Message:" + ce.getMessage());} finally {if (ossClient != null) {ossClient.shutdown();}}}
}

*注意：修改endpoint、bucketName ，bucketName 不能有重复。

运行后，在阿里云控制台查看到bucket创建成功如下
在这里插入图片描述
可以手动上传一些文件到bucket里，点击Bucket名称

进入bucket文件列表页面，通过上传文件、创建目录等方式让Bucket里得到一些目录和文件。

列举Bucket文件

package org.example;import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.common.auth.CredentialsProvider;
import com.aliyun.oss.common.auth.CredentialsProviderFactory;
import com.aliyun.oss.common.auth.DefaultCredentialProvider;
import com.aliyun.oss.common.auth.EnvironmentVariableCredentialsProvider;
import com.aliyun.oss.model.OSSObjectSummary;
import com.aliyun.oss.model.ObjectListing;public class ListFileDemo {public static void main(String[] args) throws Exception {// Endpoint以华东1（杭州）为例，其它Region请按实际情况填写。String endpoint = "https://oss-cn-shenzhen.aliyuncs.com";// 嵌入代码// RAM用户的访问密钥（AccessKey ID和AccessKey Secret）。注意修改xxx的值String accessKeyId = "xxx";String accessKeySecret = "xxx";// 使用代码嵌入的RAM用户的访问密钥配置访问凭证。CredentialsProvider credentialsProvider = new DefaultCredentialProvider(accessKeyId, accessKeySecret);// 从环境变量中获取访问凭证。运行本代码示例之前，请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。
//        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();// 填写Bucket名称，例如examplebucket。String bucketName = "examplebucket-test-test900";// 创建OSSClient实例。OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);try {// ossClient.listObjects返回ObjectListing实例，包含此次listObject请求的返回结果。ObjectListing objectListing = ossClient.listObjects(bucketName);// objectListing.getObjectSummaries获取所有文件的描述信息。for (OSSObjectSummary objectSummary : objectListing.getObjectSummaries()) {System.out.println(" - " + objectSummary.getKey() + "  " +"(size = " + objectSummary.getSize() + ")");}} catch (OSSException oe) {System.out.println("Caught an OSSException, which means your request made it to OSS, "+ "but was rejected with an error response for some reason.");System.out.println("Error Message:" + oe.getErrorMessage());System.out.println("Error Code:" + oe.getErrorCode());System.out.println("Request ID:" + oe.getRequestId());System.out.println("Host ID:" + oe.getHostId());} catch (ClientException ce) {System.out.println("Caught an ClientException, which means the client encountered "+ "a serious internal problem while trying to communicate with OSS, "+ "such as not being able to access the network.");System.out.println("Error Message:" + ce.getMessage());} finally {if (ossClient != null) {ossClient.shutdown();}}}
}

使用代码嵌入的方式得到RAM用户的访问密钥。
注意修改accessKeyId和accessKeySecret的值。
运行代码能看到一些文件
在这里插入图片描述

上传文件

package org.example;import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.common.auth.CredentialsProviderFactory;
import com.aliyun.oss.common.auth.EnvironmentVariableCredentialsProvider;
import java.io.ByteArrayInputStream;public class UploadFileDemo {public static void main(String[] args) throws Exception {// Endpoint以华东1（杭州）为例，其它Region请按实际情况填写。String endpoint = "https://oss-cn-shenzhen.aliyuncs.com";// 从环境变量中获取访问凭证。运行本代码示例之前，请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();// 填写Bucket名称，例如examplebucket。String bucketName = "examplebucket-test-test900";// 填写Object完整路径，例如exampledir/exampleobject.txt。Object完整路径中不能包含Bucket名称。String objectName = "file/uploadobject1.txt";// 创建OSSClient实例。OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);try {String content = "Hello OSS";ossClient.putObject(bucketName, objectName, new ByteArrayInputStream(content.getBytes()));} catch (OSSException oe) {System.out.println("Caught an OSSException, which means your request made it to OSS, "+ "but was rejected with an error response for some reason.");System.out.println("Error Message:" + oe.getErrorMessage());System.out.println("Error Code:" + oe.getErrorCode());System.out.println("Request ID:" + oe.getRequestId());System.out.println("Host ID:" + oe.getHostId());} catch (ClientException ce) {System.out.println("Caught an ClientException, which means the client encountered "+ "a serious internal problem while trying to communicate with OSS, "+ "such as not being able to access the network.");System.out.println("Error Message:" + ce.getMessage());} finally {if (ossClient != null) {ossClient.shutdown();}}}
}

运行后，查看阿里云控制台，多了一个uploadobject1.txt文件，
在这里插入图片描述
可以验证uploadobject1.txt的内容为

Hello OSS

下载文件

package org.example;import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.common.auth.CredentialsProviderFactory;
import com.aliyun.oss.common.auth.EnvironmentVariableCredentialsProvider;
import com.aliyun.oss.model.OSSObject;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;public class DownloadFileDemo {public static void main(String[] args) throws Exception {// Endpoint以华东1（杭州）为例，其它Region请按实际情况填写。String endpoint = "https://oss-cn-shenzhen.aliyuncs.com";// 从环境变量中获取访问凭证。运行本代码示例之前，请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();// 填写Bucket名称，例如examplebucket。String bucketName = "examplebucket-test-test900";// 填写Object完整路径，例如exampledir/exampleobject.txt。Object完整路径中不能包含Bucket名称。String objectName = "file/emp.sql";// 创建OSSClient实例。OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);try {// 调用ossClient.getObject返回一个OSSObject实例，该实例包含文件内容及文件元信息。OSSObject ossObject = ossClient.getObject(bucketName, objectName);// 调用ossObject.getObjectContent获取文件输入流，可读取此输入流获取其内容。InputStream content = ossObject.getObjectContent();if (content != null) {BufferedReader reader = new BufferedReader(new InputStreamReader(content));while (true) {String line = reader.readLine();if (line == null) {break;}System.out.println("\n" + line);//这里简单打印每行内容}// 数据读取完成后，获取的流必须关闭，否则会造成连接泄漏，导致请求无连接可用，程序无法正常工作。content.close();}} catch (OSSException oe) {System.out.println("Caught an OSSException, which means your request made it to OSS, "+ "but was rejected with an error response for some reason.");System.out.println("Error Message:" + oe.getErrorMessage());System.out.println("Error Code:" + oe.getErrorCode());System.out.println("Request ID:" + oe.getRequestId());System.out.println("Host ID:" + oe.getHostId());} catch (ClientException ce) {System.out.println("Caught an ClientException, which means the client encountered "+ "a serious internal problem while trying to communicate with OSS, "+ "such as not being able to access the network.");System.out.println("Error Message:" + ce.getMessage());} finally {if (ossClient != null) {ossClient.shutdown();}}}
}

运行程序，看到emp.sql的内容
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删除文件

package org.example;import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.common.auth.CredentialsProviderFactory;
import com.aliyun.oss.common.auth.EnvironmentVariableCredentialsProvider;public class DeleteFileDemo {public static void main(String[] args) throws Exception {// Endpoint以华东1（杭州）为例，其它Region请按实际情况填写。String endpoint = "https://oss-cn-shenzhen.aliyuncs.com";// 从环境变量中获取访问凭证。运行本代码示例之前，请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();// 填写Bucket名称，例如examplebucket。String bucketName = "examplebucket-test-test900";// 填写Object完整路径，例如exampledir/exampleobject.txt。Object完整路径中不能包含Bucket名称。String objectName = "file/uploadobject1.txt";// 创建OSSClient实例。OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);try {// 删除文件。ossClient.deleteObject(bucketName, objectName);} catch (OSSException oe) {System.out.println("Caught an OSSException, which means your request made it to OSS, "+ "but was rejected with an error response for some reason.");System.out.println("Error Message:" + oe.getErrorMessage());System.out.println("Error Code:" + oe.getErrorCode());System.out.println("Request ID:" + oe.getRequestId());System.out.println("Host ID:" + oe.getHostId());} catch (ClientException ce) {System.out.println("Caught an ClientException, which means the client encountered "+ "a serious internal problem while trying to communicate with OSS, "+ "such as not being able to access the network.");System.out.println("Error Message:" + ce.getMessage());} finally {if (ossClient != null) {ossClient.shutdown();}}}
}

运行程序后，刷新Bucket列表，看到file/uploadobject1.txt被删除了。
在这里插入图片描述
代码总结：
在使用OSS SDK时，需要先创建OSSClient实例ossClient，然后调用对应API方法。例如：

创建Bucket： ossClient.createBucket(bucketName)
列举Bucket文件： ossClient.listObjects(bucketName)
上传文件：ossClient.putObject(bucketName, objectName, new ByteArrayInputStream(content.getBytes()))
下载文件：ossClient.getObject(bucketName, objectName).getObjectContent()
删除文件：ossClient.deleteObject(bucketName, objectName)

完成！enjoy it！