Object Storage Service：Java擷取對象標籤

注意事項

• 本文以華東1（杭州）外網Endpoint為例。如果您希望通過與OSS同地區的其他阿里雲產品訪問OSS，請使用內網Endpoint。關於OSS支援的Region與Endpoint的對應關係，請參見OSS訪問網域名稱、資料中心、開放連接埠。

• 本文以從環境變數讀取存取憑證為例。如何配置訪問憑證，請參見Java配置訪問憑證。

• 本文以OSS網域名稱建立OSSClient為例。如果您希望通過自訂網域名、STS等方式建立OSSClient，請參見建立OSSClient。

• 要擷取對象標籤，您必須具有oss:GetObjectTagging許可權。具體操作，請參見為RAM使用者授權自訂的權限原則。

擷取Object標籤資訊

當儲存空間（Bucket）未開啟版本控制時，您可以根據需要擷取Object標籤資訊。當Bucket已開啟版本控制時，OSS預設只擷取Object目前的版本標籤資訊。

以下代碼用於擷取目標儲存空間examplebucket中exampledir目錄下的exampleobject.txt檔案的標籤資訊。

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.util.*;

public class Demo {
    public static void main(String[] args) throws Throwable {
        // Endpoint以華東1（杭州）為例，其它Region請按實際情況填寫。
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // 從環境變數中擷取訪問憑證。運行本程式碼範例之前，請確保已設定環境變數OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // 填寫Bucket名稱，例如examplebucket。
        String bucketName = "examplebucket";
        // 填寫Object完整路徑，例如exampledir/exampleobject.txt。Object完整路徑中不能包含Bucket名稱。
        String objectName = "exampledir/exampleobject.txt";
        // 填寫Bucket所在地區。以華東1（杭州）為例，Region填寫為cn-hangzhou。
        String region = "cn-hangzhou";

        // 建立OSSClient執行個體。
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);        
        OSS ossClient = OSSClientBuilder.create()
        .endpoint(endpoint)
        .credentialsProvider(credentialsProvider)
        .clientConfiguration(clientBuilderConfiguration)
        .region(region)               
        .build();

        try {
            // 擷取檔案的標籤。
            TagSet tagSet = ossClient.getObjectTagging(bucketName, objectName);
            Map<String, String> tags = tagSet.getAllTags();

            // 查看標籤資訊。
            System.out.println("object tagging: "+ tags.toString());
        } 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();
            }
        }
    }
}

擷取Object指定版本標籤資訊

當Bucket已開啟版本控制時，通過指定Object的版本ID（versionId），您可以擷取Object指定版本標籤資訊。

以下代碼用於擷取目標儲存空間examplebucket中exampledir目錄下的exampleobject.txt檔案指定版本的標籤資訊。

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;

public class Demo {
    public static void main(String[] args) throws Throwable {
        // Endpoint以華東1（杭州）為例，其它Region請按實際情況填寫。
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // 從環境變數中擷取訪問憑證。運行本程式碼範例之前，請確保已設定環境變數OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // 填寫Bucket名稱，例如examplebucket。
        String bucketName = "examplebucket";
        // 填寫Object完整路徑，例如exampledir/exampleobject.txt。Object完整路徑中不能包含Bucket名稱。
        String objectName = "exampledir/exampleobject.txt";
        // 填寫Object的版本ID，例如CAEQMxiBgICAof2D0BYiIDJhMGE3N2M1YTI1NDQzOGY5NTkyNTI3MGYyMzJm****。
        String versionId = "CAEQMxiBgICAof2D0BYiIDJhMGE3N2M1YTI1NDQzOGY5NTkyNTI3MGYyMzJm****";
        // 填寫Bucket所在地區。以華東1（杭州）為例，Region填寫為cn-hangzhou。
        String region = "cn-hangzhou";

        // 建立OSSClient執行個體。
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);        
        OSS ossClient = OSSClientBuilder.create()
        .endpoint(endpoint)
        .credentialsProvider(credentialsProvider)
        .clientConfiguration(clientBuilderConfiguration)
        .region(region)               
        .build();

        try {
            GenericRequest genericRequest = new GenericRequest(bucketName, objectName, versionId);
            TagSet tagSet = ossClient.getObjectTagging(genericRequest);

            // 查看標籤資訊。
            System.out.println("object tagging: "+ tagSet.toString());
        } 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();
            }
        }
    }
}

相關文檔

• 關於擷取對象標籤的完整範例程式碼，請參見GitHub樣本。

• 關於擷取對象標籤的API介面說明，請參見GetObjectTagging。