java - Java中检查S3存储桶是否具有与通配符模式匹配的键的对象的方法

Question

Scala 或 Java 程序检查 S3 存储桶是否具有与特定键模式匹配的对象的好方法是什么？也就是说，如果我有一个名为“CsvBucket”的存储桶，我如何检查它是否包含键匹配模式“processed/files/2015/8/*.csv”的对象？

谢谢

Answer 1

由于 S3 对象键只是Strings，因此您可以遍历它们并使用正则表达式测试每个键。也许是这样的（使用jets3t库）：

Pattern pattern = Pattern.compile(".*\\.csv");
// 'service' is an instance of S3Service
S3Bucket bucket = service.getBucket(bucketName);
S3Object[] files = service.listObjects(bucket, "processed/files/2015/8", null);
for (int i = 0; i < files.length; i++)
{
    if (pattern.matches(files[i].getKey()))
    {
        // ... work with the file ...
    }
}

Answer 2

另一种方法 - http://docs.aws.amazon.com/AmazonS3/latest/dev/ListingObjectKeysUsingJava.html

import java.io.IOException;
import com.amazonaws.AmazonClientException;
import com.amazonaws.AmazonServiceException;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.ListObjectsRequest;
import com.amazonaws.services.s3.model.ListObjectsV2Request;
import com.amazonaws.services.s3.model.ListObjectsV2Result;
import com.amazonaws.services.s3.model.ObjectListing;
import com.amazonaws.services.s3.model.S3ObjectSummary;

public class ListKeys {
private static String bucketName = "***bucket name***";

public static void main(String[] args) throws IOException {
    AmazonS3 s3client = new AmazonS3Client(new ProfileCredentialsProvider());
    try {
        System.out.println("Listing objects");
        final ListObjectsV2Request req = new ListObjectsV2Request().withBucketName(bucketName).withMaxKeys(2);
        ListObjectsV2Result result;
        do {               
           result = s3client.listObjectsV2(req);

           for (S3ObjectSummary objectSummary : 
               result.getObjectSummaries()) {
               System.out.println(" - " + objectSummary.getKey() + "  " +
                       "(size = " + objectSummary.getSize() + 
                       ")");
           }
           System.out.println("Next Continuation Token : " + result.getNextContinuationToken());
           req.setContinuationToken(result.getNextContinuationToken());
        } while(result.isTruncated() == true ); 

     } catch (AmazonServiceException ase) {
        System.out.println("Caught an AmazonServiceException, " +
                "which means your request made it " +
                "to Amazon S3, but was rejected with an error response " +
                "for some reason.");
        System.out.println("Error Message:    " + ase.getMessage());
        System.out.println("HTTP Status Code: " + ase.getStatusCode());
        System.out.println("AWS Error Code:   " + ase.getErrorCode());
        System.out.println("Error Type:       " + ase.getErrorType());
        System.out.println("Request ID:       " + ase.getRequestId());
    } catch (AmazonClientException ace) {
        System.out.println("Caught an AmazonClientException, " +
                "which means the client encountered " +
                "an internal error while trying to communicate" +
                " with S3, " +
                "such as not being able to access the network.");
        System.out.println("Error Message: " + ace.getMessage());
    }
}

}