AWS S3 上传下载文件

前言

　　Amazon文件服务器的使用，本章之记录文件的上传和下载。

pom依赖

　　首先添加依赖

  <dependency>
     <groupId>com.amazonaws</groupId>
     <artifactId>aws-java-sdk-s3</artifactId>
     <version>1.11.336</version>
   </dependency>

正文

提供个工具类

public class FileUtils {
    // 【你的 access_key】
    static final String AWS_ACCESS_KEY = "*********";
    // 【你的 aws_secret_key】
    static final String AWS_SECRET_KEY = "*********************";
    // 储存桶的名称
    static final String BUCKET_NAME = "app-file-upload";
    // 设置服务器所属地区
    static final Regions REGION = Regions.DEFAULT_REGION;
    // 储存路径
    static final String PATH = "uploadExcel";

    static final BasicAWSCredentials awsCreds = new BasicAWSCredentials(AWS_ACCESS_KEY, AWS_SECRET_KEY);

    static final AmazonS3 s3 = AmazonS3ClientBuilder.standard()
            .withCredentials(new AWSStaticCredentialsProvider(awsCreds)).withRegion(REGION).build();

    @Autowired
    protected HttpServletRequest request;

    @Autowired
    protected HttpServletResponse response;

    /**
     * 上传到文件返回一个文件储存后的路径
     * 
     * @param multipartFile
     * @return
     * @throws IOException
     * @throws SdkClientException
     * @throws AmazonServiceException
     * @throws Exception
     */
    public static String uploadFileToS3(MultipartFile multipartFile, String type)
            throws AmazonServiceException, SdkClientException, IOException {
        if (multipartFile.isEmpty()) {
            return "文件为空";
        }
        String dateString = DateUtils.convertToDate(LocalDate.now());
        long time = System.currentTimeMillis();
        // 拼接下文件路径，为了不会出现文件覆盖现象，加上时间戳
        String s3FilePath = PATH + "/" + type + "/" + dateString + "/" + time + "/"
                + multipartFile.getOriginalFilename();
        ObjectMetadata metadata = new ObjectMetadata();
        metadata.setContentType(multipartFile.getContentType());
        metadata.setContentLength(multipartFile.getSize());
        // 开始上传文件
        s3.putObject(BUCKET_NAME, s3FilePath, multipartFile.getInputStream(), metadata);
        // 返回文件位置
        return s3FilePath;
    }

    /**
     * 用文件路径获取文件下载地址
     * 
     * @param path
     * @return
     */
    public static String getDownloadFileFromS3(String path) {
        return s3.generatePresignedUrl(new GeneratePresignedUrlRequest(BUCKET_NAME, path)).toString();
    }

    /**
     * 获取S3Object对象
     * 
     * @param path
     * @return
     */
    public static S3Object getS3Object(String path) {
        S3Object s3Object = s3.getObject(BUCKET_NAME, path);
        return s3Object;
    }
}

S3Object 对象中有输入流，可以使用创建文件。