Java中的方式檢查S3存儲桶是否具有與通配符模式匹配的鍵的對象

Question

從Scala或Java程序檢查S3存儲桶是否具有匹配某個特定鍵模式的對象的好方法是什麼？也就是說，如果我有一個名爲「CsvBucket」的桶，我該如何檢查它是否包含鍵匹配模式「processed/files/2015/8/*。csv」的對象？

感謝

Answer 1

由於S3對象鍵只是String是你可以只在它們之間迭代，並使用正則表達式測試每個。也許這樣的事情（使用jets3t庫）：

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

另一種方式來做到這一點 - 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()); 
    } 
} 

}