Java中如何操作云存储？AWS S3 SDK集成

<dependency>
    <groupId>software.amazon.awssdk</groupId>
    <artifactId>s3</artifactId>
    <version>2.20.100</version> <!-- 请使用最新稳定版本 -->
</dependency>
<dependency>
    <groupId>software.amazon.awssdk</groupId>
    <artifactId>auth</artifactId>
    <version>2.20.100</version>
</dependency>
<dependency>
    <groupId>software.amazon.awssdk</groupId>
    <artifactId>regions</artifactId>
    <version>2.20.100</version>
</dependency>

import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.*;
import software.amazon.awssdk.core.sync.RequestBody;
import software.amazon.awssdk.core.ResponseInputStream;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;

public class S3Operations {

    private S3Client s3Client;
    private String bucketName;

    public S3Operations(String bucketName, Region region) {
        this.bucketName = bucketName;
        // 构建S3客户端。SDK会自动尝试从环境变量、JVM系统属性、~/.aws/credentials文件等地方加载凭证。
        // 如果在EC2实例上运行，它还会自动利用IAM角色凭证。
        this.s3Client = S3Client.builder()
                .region(region)
                .build();
    }

    /**
     * 上传文件到S3
     * @param keyName S3上的对象键名 (路径+文件名)
     * @param filePath 本地文件路径
     */
    public void uploadFile(String keyName, String filePath) {
        try {
            PutObjectRequest putObjectRequest = PutObjectRequest.builder()
                    .bucket(bucketName)
                    .key(keyName)
                    .build();

            s3Client.putObject(putObjectRequest, RequestBody.fromFile(Paths.get(filePath)));
            System.out.println("文件 '" + filePath + "' 已成功上传到 S3://"+ bucketName + "/" + keyName);
        } catch (S3Exception e) {
            System.err.println("上传文件到S3失败: " + e.getMessage());
            // 进一步处理特定错误码，比如权限不足等
        } catch (IOException e) {
            System.err.println("读取本地文件失败: " + e.getMessage());
        }
    }

    /**
     * 从S3下载文件
     * @param keyName S3上的对象键名
     * @param downloadPath 本地保存路径
     */
    public void downloadFile(String keyName, String downloadPath) {
        try {
            GetObjectRequest getObjectRequest = GetObjectRequest.builder()
                    .bucket(bucketName)
                    .key(keyName)
                    .build();

            ResponseInputStream<GetObjectResponse> s3Object = s3Client.getObject(getObjectRequest);
            Files.copy(s3Object, Paths.get(downloadPath));
            System.out.println("文件 '" + keyName + "' 已成功从 S3 下载到 " + downloadPath);
        } catch (S3Exception e) {
            System.err.println("从S3下载文件失败: " + e.getMessage());
        } catch (IOException e) {
            System.err.println("写入本地文件失败: " + e.getMessage());
        }
    }

    /**
     * 删除S3上的文件
     * @param keyName S3上的对象键名
     */
    public void deleteFile(String keyName) {
        try {
            DeleteObjectRequest deleteObjectRequest = DeleteObjectRequest.builder()
                    .bucket(bucketName)
                    .key(keyName)
                    .build();

            s3Client.deleteObject(deleteObjectRequest);
            System.out.println("文件 '" + keyName + "' 已成功从 S3 删除。");
        } catch (S3Exception e) {
            System.err.println("删除S3文件失败: " + e.getMessage());
        }
    }

    /**
     * 列出S3桶中的对象
     */
    public void listObjects() {
        try {
            ListObjectsV2Request listObjectsV2Request = ListObjectsV2Request.builder()
                    .bucket(bucketName)
                    .build();

            ListObjectsV2Response listObjectsV2Response = s3Client.listObjectsV2(listObjectsV2Request);
            System.out.println("S3桶 '" + bucketName + "' 中的对象:");
            listObjectsV2Response.contents().forEach(obj ->
                    System.out.println("- " + obj.key() + " (大小: " + obj.size() + " 字节)"));
        } catch (S3Exception e) {
            System.err.println("列出S3对象失败: " + e.getMessage());
        }
    }

    public void close() {
        if (s3Client != null) {
            s3Client.close();
        }
    }

    public static void main(String[] args) {
        String myBucketName = "your-unique-s3-bucket-name"; // 替换为你的S3桶名
        Region myRegion = Region.AP_NORTHEAST_1; // 替换为你的S3桶所在区域，比如东京区域

        S3Operations s3Ops = new S3Operations(myBucketName, myRegion);

        // 示例：上传文件
        String localFilePath = "path/to/your/local/file.txt"; // 替换为本地文件路径
        String s3KeyName = "my-folder/uploaded-file.txt"; // 替换为S3上的键名
        // s3Ops.uploadFile(s3KeyName, localFilePath);

        // 示例：下载文件
        String downloadFilePath = "path/to/save/downloaded-file.txt"; // 替换为下载保存路径
        // s3Ops.downloadFile(s3KeyName, downloadFilePath);

        // 示例：列出对象
        // s3Ops.listObjects();

        // 示例：删除文件
        // s3Ops.deleteFile(s3KeyName);

        s3Ops.close();
    }
}

import software.amazon.awssdk.transfer.s3.S3TransferManager;
import software.amazon.awssdk.transfer.s3.model.UploadFileRequest;
import software.amazon.awssdk.transfer.s3.model.UploadFileResponse;
import software.amazon.awssdk.transfer.s3.progress.LoggingTransferListener; // 用于查看进度

import java.nio.file.Paths;
import java.util.concurrent.CompletableFuture;

// ... 在S3Operations类中添加或独立使用

public void uploadLargeFileWithTransferManager(String keyName, String filePath) {
    // S3TransferManager 内部会管理 S3Client 的生命周期，但也可以传入已有的 S3Client
    try (S3TransferManager transferManager = S3TransferManager.builder()
            .s3Client(s3Client) // 使用之前创建的s3Client
            .build()) {

        UploadFileRequest uploadFileRequest = UploadFileRequest.builder()
                .putObjectRequest(b -> b.bucket(bucketName).key(keyName))
                .source(Paths.get(filePath))
                // 可以添加监听器来追踪上传进度
                .addTransferListener(LoggingTransferListener.create())
                .build();

        // 异步上传，返回一个CompletableFuture
        CompletableFuture<UploadFileResponse> upload = transferManager.uploadFile(uploadFileRequest).completionFuture();

        // 等待上传完成
        upload.join();
        System.out.println("大文件 '" + filePath + "' 已成功通过TransferManager上传到 S3://"+ bucketName + "/" + keyName);

    } catch (Exception e) {
        System.err.println("上传大文件失败: " + e.getMessage());
    }
}

import software.amazon.awssdk.transfer.s3.S3TransferManager;
import software.amazon.awssdk.transfer.s3.model.DownloadFileRequest;
import software.amazon.awssdk.transfer.s3.model.DownloadFileResponse;

// ... 在S3Operations类中添加或独立使用

public void downloadLargeFileWithTransferManager(String keyName, String downloadPath) {
    try (S3TransferManager transferManager = S3TransferManager.builder()
            .s3Client(s3Client)
            .build()) {

        DownloadFileRequest downloadFileRequest = DownloadFileRequest.builder()
                .getObjectRequest(b -> b.bucket(bucketName).key(keyName))
                .destination(Paths.get(downloadPath))
                .addTransferListener(LoggingTransferListener.create())
                .build();

        CompletableFuture<DownloadFileResponse> download = transferManager.downloadFile(downloadFileRequest).completionFuture();

        download.join();
        System.out.println("大文件 '" + keyName + "' 已成功通过TransferManager下载到 " + downloadPath);

    } catch (Exception e) {
        System.err.println("下载大文件失败: " + e.getMessage());
    }
}