# 将 Amazon Simple Storage Service（Amazon S3）桶中的所有对象下载到本地目录
<a name="s3_example_s3_DownloadBucketToDirectory_section"></a>

以下代码示例演示了如何将 Amazon Simple Storage Service（Amazon S3）桶中的所有对象下载到本地目录。

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#### [ Java ]

**适用于 Java 的 SDK 2.x**  
 查看 GitHub，了解更多信息。在 [Amazon 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/s3#code-examples)中查找完整示例，了解如何进行设置和运行。
使用 [S3TransferManager](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/transfer/s3/S3TransferManager.html) [下载同一个 S3 存储桶中的所有 S3 对象](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/transfer/s3/S3TransferManager.html#downloadDirectory(software.amazon.awssdk.transfer.s3.DownloadDirectoryRequest))。查看[完整文件](https://github.com/awsdocs/aws-doc-sdk-examples/blob/main/javav2/example_code/s3/src/main/java/com/example/s3/transfermanager/DownloadToDirectory.java)并[进行测试](https://github.com/awsdocs/aws-doc-sdk-examples/blob/main/javav2/example_code/s3/src/test/java/TransferManagerTest.java)。  

```
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import software.amazon.awssdk.core.sync.RequestBody;
import software.amazon.awssdk.services.s3.model.ObjectIdentifier;
import software.amazon.awssdk.transfer.s3.S3TransferManager;
import software.amazon.awssdk.transfer.s3.model.CompletedDirectoryDownload;
import software.amazon.awssdk.transfer.s3.model.DirectoryDownload;
import software.amazon.awssdk.transfer.s3.model.DownloadDirectoryRequest;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.HashSet;
import java.util.Set;
import java.util.UUID;
import java.util.stream.Collectors;

    public Integer downloadObjectsToDirectory(S3TransferManager transferManager,
            URI destinationPathURI, String bucketName) {
        DirectoryDownload directoryDownload = transferManager.downloadDirectory(DownloadDirectoryRequest.builder()
                .destination(Paths.get(destinationPathURI))
                .bucket(bucketName)
                .build());
        CompletedDirectoryDownload completedDirectoryDownload = directoryDownload.completionFuture().join();

        completedDirectoryDownload.failedTransfers()
                .forEach(fail -> logger.warn("Object [{}] failed to transfer", fail.toString()));
        return completedDirectoryDownload.failedTransfers().size();
    }
```
+  有关 API 详细信息，请参阅《Amazon SDK for Java 2.x API 参考》**中的 [DownloadDirectory](https://docs.amazonaws.cn/goto/SdkForJavaV2/s3-2006-03-01/DownloadDirectory)。

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有关 Amazon SDK 开发人员指南和代码示例的完整列表，请参阅 [使用 Amazon SDK 通过 Amazon S3 进行开发](sdk-general-information-section.md)。本主题还包括有关入门的信息以及有关先前的 SDK 版本的详细信息。