**注意**：亚马逊 WorkDocs不再提供新买家注册和账户升级服务。在此处了解迁移步骤：[如何从中迁移数据 WorkDocs](https://aws.amazon.com/blogs/business-productivity/how-to-migrate-content-from-amazon-workdocs)。

本文属于机器翻译版本。若本译文内容与英语原文存在差异，则一律以英文原文为准。

# WorkDocs 通过扮演角色进行连接
<a name="connect-workdocs-role"></a>

此示例使用 AWS Java SDK 代入角色并使用该角色的临时安全证书进行访问 WorkDocs。该代码示例使用 [DescribeFolderContents](https://docs.aws.amazon.com/workdocs/latest/APIReference/API_DescribeFolderContents.html)API 列出用户文件夹中的项目。

```
import java.util.ArrayList;
import java.util.List;

import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.auth.BasicSessionCredentials;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.securitytoken.AWSSecurityTokenService;
import com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClientBuilder;
import com.amazonaws.services.securitytoken.model.AssumeRoleRequest;
import com.amazonaws.services.securitytoken.model.AssumeRoleResult;
import com.amazonaws.services.workdocs.AmazonWorkDocs;
import com.amazonaws.services.workdocs.AmazonWorkDocsClient;
import com.amazonaws.services.workdocs.model.DescribeFolderContentsRequest;
import com.amazonaws.services.workdocs.model.DescribeFolderContentsResult;
import com.amazonaws.services.workdocs.model.DocumentMetadata;
import com.amazonaws.services.workdocs.model.FolderMetadata;

public class AssumeRoleDemo {
  private static final String DEMO_ROLE_ARN = "{{arn:aws:iam::111122223333:role/workdocs-readonly-role}}";
  private static AmazonWorkDocs workDocs;

  public static void main(String[] args) throws Exception {

    AWSCredentials longTermCredentials =
        new BasicAWSCredentials("{{accessKey}}", "{{secretKey}}");

    // Use developer’s long-term credentials to call the AWS Security Token Service (STS) 
	// AssumeRole API, specifying the ARN for the role workdocs-readonly-role in 
	// 3rd party AWS account.

    AWSSecurityTokenService stsClient =
        AWSSecurityTokenServiceClientBuilder.standard()
            .withCredentials(new AWSStaticCredentialsProvider(longTermCredentials))
            .withRegion(Regions.DEFAULT_REGION.getName()).build();;

    // If you are accessing a 3rd party account, set ExternalId 
    // on assumeRequest using the withExternalId() function.
    AssumeRoleRequest assumeRequest =
        new AssumeRoleRequest().withRoleArn(DEMO_ROLE_ARN).withDurationSeconds(3600)
            .withRoleSessionName("demo");

    AssumeRoleResult assumeResult = stsClient.assumeRole(assumeRequest);

    // AssumeRole returns temporary security credentials for the 
	// workdocs-readonly-role

    BasicSessionCredentials temporaryCredentials =
        new BasicSessionCredentials(assumeResult.getCredentials().getAccessKeyId(), assumeResult
            .getCredentials().getSecretAccessKey(), assumeResult.getCredentials().getSessionToken());

    // Build WorkDocs client using the temporary credentials. 
    workDocs =
        AmazonWorkDocsClient.builder()
            .withCredentials(new AWSStaticCredentialsProvider(temporaryCredentials))
            .withRegion(Regions.US_WEST_2).build();


    // Invoke WorkDocs service calls using the temporary security credentials
    // obtained for workdocs-readonly-role. In this case a call has been made 
	// to get metadata of Folders and Documents present in a user’s root folder.

    describeFolder("{{root-folder-id}}");
  }

  private static void describeFolder(String folderId) {
    DescribeFolderContentsRequest request = new DescribeFolderContentsRequest();
    request.setFolderId(folderId);
    request.setLimit(2);
    List<DocumentMetadata> documents = new ArrayList<>();
    List<FolderMetadata> folders = new ArrayList<>();
    
    String marker = null;
    
    do {
      request.setMarker(marker);
      DescribeFolderContentsResult result = workDocs.describeFolderContents(request);
      documents.addAll(result.getDocuments());
      folders.addAll(result.getFolders());
      marker = result.getMarker();
    } while (marker != null);
    
    for (FolderMetadata folder : folders)
      System.out.println("Folder:" + folder.getName());
    for (DocumentMetadata document : documents)
      System.out.println("Document:" + document.getLatestVersionMetadata().getName());
  }
}
```