Object Storage Service:Consultar as tags de um objeto (OSS SDK for Java 1.0)

Observações de uso

• Este tópico usa o endpoint público da região china (Hangzhou). Para acessar o oss a partir de outros service Alibaba Cloud na mesma região, use um endpoint interno. Para mais detalhes sobre regiões e endpoints compatíveis, consulte Regions and endpoints.

• Neste tópico, as credenciais de acesso são obtidas de variáveis de ambiente. Para mais informações, consulte 配置访问凭证.

• Este tópico demonstra como crie uma instância OSSClient com um endpoint do oss. Para configurações alternativas, como usar um domínio personalizado ou autenticar com credenciais do Security Token Service (STS), consulte Client configuration.

• Para consultar as tags de um objeto, você precisa ter a permissão oss:GetObjectTagging. Para mais informações, consulte Grant a custom policy.

Consultar as tags de um objeto

Se o versionamento não estiver ativado para o bucket que armazena o objeto, consulte as tags conforme sua necessidade. Quando o versionamento está ativado, o oss retorna as tags da versão atual do objeto por padrão.

O código de exemplo a seguir mostra como consultar as tags do objeto exampleobject.txt no diretório exampledir do bucket examplebucket:

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 {
        // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. 
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // Specify the name of the bucket. Example: examplebucket. 
        String bucketName = "examplebucket";
        // Specify the full path of the object. Example: exampledir/exampleobject.txt. Do not include the bucket name in the full path. 
        String objectName = "exampledir/exampleobject.txt";
        // Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou.
        String region = "cn-hangzhou";

        // Create an OSS Client instance. 
        // Call the shutdown method to release associated resources when the OSS Client is no longer in use.
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);        
        OSS ossClient = OSSClientBuilder.create()
        .endpoint(endpoint)
        .credentialsProvider(credentialsProvider)
        .clientConfiguration(clientBuilderConfiguration)
        .region(region)               
        .build();

        try {
            // Query the tags of the object. 
            TagSet tagSet = ossClient.getObjectTagging(bucketName, objectName);
            Map<String, String> tags = tagSet.getAllTags();

            // View the tags of the object. 
            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();
            }
        }
    }
}

Consultar as tags de uma versão específica de um objeto

Se o versionamento estiver ativado para o bucket que armazena o objeto, você pode consultar as tags de uma versão específica especificando o ID de versão correspondente.

O código de exemplo a seguir mostra como consultar as tags de uma versão específica do objeto exampleobject.txt no diretório exampledir do bucket examplebucket:

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 {
        // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. 
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // Specify the name of the bucket. Example: examplebucket. 
        String bucketName = "examplebucket";
        // Specify the full path of the object. Example: exampledir/exampleobject.txt. Do not include the bucket name in the full path. 
        String objectName = "exampledir/exampleobject.txt";
        // Specify the version ID of the object. Example: CAEQMxiBgICAof2D0BYiIDJhMGE3N2M1YTI1NDQzOGY5NTkyNTI3MGYyMzJm****. 
        String versionId = "CAEQMxiBgICAof2D0BYiIDJhMGE3N2M1YTI1NDQzOGY5NTkyNTI3MGYyMzJm****";
        // Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou.
        String region = "cn-hangzhou";

        // Create an OSS Client instance. 
        // Call the shutdown method to release associated resources when the OSS Client is no longer in use.
        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);

            // View the tags of the object. 
            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();
            }
        }
    }
}

Referências

• Para acessar o código de exemplo completo usado para consultar as tags de um objeto, visualize o GitHub.

• Para mais informações sobre a operação de API usada para consultar as tags de um objeto, consulte GetObjectTagging.