Question

我们在S3上存储了一些数据，并希望能够获取最近上传的文件。

有关实现此目标的最佳方法的任何建议吗？

我们目前正在使用jets3t库。

Answer 1

这可能会有所帮助..

S3Service s3Service = new S3Service(providerCredentials);

Date tempDate = null;
S3Object recentObj = null;

for(S3Object object : s3Service.listObjects("bucketName")) {
    modifiedDate =(Date)object.getMetadata(BaseStorageItem.METADATA_HEADER_LAST_MODIFIED_DATE); 
    if(tempDate == null) {
        tempDate = modifiedDate;
    } else {
        if(modifiedDate.compareTo(tempDate) < 0) {
             tempDate = modifiedDate;
             recentObj = object;
    }
    }
 }

我还没有测试过这段代码。希望这会有所帮助..

Answer 2

使用Spring Boot：

@Service
public class AWSS3Service {

private static final Logger LOGGER = LogManager.getLogger(AWSS3Service.class);

@Autowired
private AmazonS3 amazonS3;

@Value("${aws.s3.bucket}")
private String bucketName;

@Value("${aws.s3.folder.download}")
private String foldernameDownload;

public byte[] downloadFile(final String typeName) {
    
    byte[] content = null;
    LOGGER.info("Downloading most recent file from {}",  typeName);
    
    ObjectListing objects = amazonS3.listObjects(bucketName,foldernameDownload+"/"+ typeName+"/");
    
    Date tempDate = null;
    S3ObjectSummary recentObj = null;
    
    List<S3ObjectSummary> objectSummaries = objects.getObjectSummaries();
    for (S3ObjectSummary objectSummary : objectSummaries) {
        
        if (objectSummary.getSize()<=0)
            continue;
        
        Date modifiedDate = objectSummary.getLastModified();
        
        if(tempDate == null || modifiedDate.compareTo(tempDate) > 0) {
            tempDate = modifiedDate;
            recentObj = objectSummary;
        } 
    }
    
    String obKey ="";
    if(recentObj != null)
        obKey = recentObj.getKey();
    else
        return content;//no files found
    
    S3Object s3Object = amazonS3.getObject(bucketName,obKey);
    S3ObjectInputStream stream = s3Object.getObjectContent();
    try {
        content = IOUtils.toByteArray(stream);
        LOGGER.info("File downloaded successfully.");
        s3Object.close();
    } catch(final IOException ex) {
        LOGGER.error("IO Error Message= {}", ex.getMessage());
    }
    return content;
}
}

扫描S3以获取最新文件

2 个答案: