我在Amazon S3中有一个桶，其结构如下：
bucket-name/prefix1/prefix2/prefix3/prefix4/file1.txt
bucket-name/prefix1/prefix2/prefix3/prefix4/prefix5/file2.txt
bucket-name/prefix1/prefix2/prefix3/file3.txt
我想只列出像这样的前缀名称
prefix1
prefix1/prefix2
prefix1/prefix2/prefix3
prefix1/prefix2/prefix3/prefix4
prefix1/prefix2/prefix3/prefix4/prefix5
我如何列出这些前缀？
我正在重新列出
列表 List<S3ObjectSummary> keyList = new ArrayList<S3ObjectSummary>();
ObjectListing objects = s3Client.listObjects(bucketName);
keyList.addAll(objects.getObjectSummaries());
while (objects.isTruncated()) {
objects = s3Client.listNextBatchOfObjects(objects);
keyList.addAll(objects.getObjectSummaries());
}
for (String prefix : prefixes) {
System.out.println(prefix);
}
它给出的列表为： -
elasticmapreduce/j-1T09V6RUT8JO/containers/application_1475040945730_0006/container_1475040945730_0006_01_000001/stderr.gz
elasticmapreduce/j-1T09V6RUT8JO/containers/application_1475040945730_0006/container_1475040945730_0006_01_000002/stderr.gz
elasticmapreduce/j-1T09V6RUT8JO/containers/application_1475040945730_0006/container_1475040945730_0006_01_000002/stdout.gz
elasticmapreduce/j-1T09V6RUT8JO/containers/application_1475040945730_0006/container_1475040945730_0006_01_000003/stderr.gz
elasticmapreduce/j-1T09V6RUT8JO/containers/application_1475040945730_0006/container_1475040945730_0006_01_000003/stdout.gz
elasticmapreduce/j-1T09V6RUT8JO/containers/application_1475040945730_0007/container_1475040945730_0007_01_000001/stderr.gz
elasticmapreduce/j-1T09V6RUT8JO/containers/application_1475040945730_0007/container_1475040945730_0007_01_000002/stderr.gz
elasticmapreduce/j-1T09V6RUT8JO/containers/application_1475040945730_0007/container_1475040945730_0007_01_000002/stdout.gz
...
但我想要如上所述的列表。
答案 0 :(得分：4)
我找到了解决问题的方法。在这里，我正在分享我对上述问题的解决方案：
package com.elegant.amazon;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.AmazonS3Exception;
import com.amazonaws.services.s3.model.Bucket;
import com.amazonaws.services.s3.model.ListObjectsRequest;
import com.amazonaws.services.s3.model.ObjectListing;
import com.amazonaws.services.s3.model.S3ObjectSummary;
/**
* A utility class for Amazon S3 Service. It has common methods init. which is
* used for all common purpose. Amazon S3 client is initialized when class is
* deployed on the server. for the connection I have used BasicAWSCredentials
* Class. It sets all the necessary information for accessing Amazon S3 Service
* like Access Key and Secret Key. It will load all buckets information when
* it's deployed on the server.
*
* @author Vipin Suman
*
* @since May 5th,2017
*/
@SuppressWarnings("deprecation")
public class AmazonS3Util {
public static AmazonS3 s3Client = null;
public static List<Bucket> bucketList = null;
static {
try {
/** Setting Up AWS Credentials For accessing Amazon S3 */
BasicAWSCredentials awsCredentials = new BasicAWSCredentials(AWSCommonConstants.ACCESS_KEY,
AWSCommonConstants.SECRET_KEY);
/** initializing AmazonS3 Client */
s3Client = new AmazonS3Client(awsCredentials);
/** initializing all buckets stored inside Amazon S3 */
bucketList = s3Client.listBuckets();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* Returns List<Bucket> object. It has informations of all buckets. It
* stores information of all bucket when class is deployed on the server.
*/
public static List<Bucket> getAllBuckets() {
return bucketList;
}
/**
* Returns HashMap object for which has prefixList and dataList init. in
* this method we are getting all common prefixes list and data list for the
* given bucket.
*
* This method is called when we are giving only bucketName as Parameter.
*
* @param bucketName
*
*/
public static HashMap<String, List<String>> getPrefix(String bucketName) {
Long startTime = System.currentTimeMillis();
ListObjectsRequest listObjectsRequest = null;
ObjectListing objectListing = null;
HashMap<String, List<String>> prefixData = null;
try {
listObjectsRequest = new ListObjectsRequest().withBucketName(bucketName).withDelimiter(AWSCommonConstants.FILE_DELIMITER);
prefixData = prepareDataMap(listObjectsRequest, objectListing);
} catch (AmazonS3Exception e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
System.out.println("Total Time Taken : " + (System.currentTimeMillis() - startTime));
return prefixData;
}
/**
* Returns HashMap object for which has prefixList and dataList init. in
* this method we are getting all common prefixes list and data list for the
* given bucket.
*
* This method is called when we give only bucketName and prefix as
* Parameter.
*
* @param bucketName
*
* @param prefix
*/
public static HashMap<String, List<String>> getPrefix(String bucketName, String prefix) {
Long startTime = System.currentTimeMillis();
ListObjectsRequest listObjectsRequest = null;
ObjectListing objectListing = null;
HashMap<String, List<String>> prefixData = null;
try {
if (!prefix.endsWith(AWSCommonConstants.FILE_DELIMITER)) {
prefix += AWSCommonConstants.FILE_DELIMITER;
}
listObjectsRequest = new ListObjectsRequest().withBucketName(bucketName).withPrefix(prefix).withDelimiter(AWSCommonConstants.FILE_DELIMITER);
prefixData = prepareDataMap(listObjectsRequest, objectListing);
} catch (AmazonS3Exception e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
System.out.println("Total Time Taken : " + (System.currentTimeMillis() - startTime));
return prefixData;
}
/**
* Returns HashMap object. It prepares the HashMap object for the above
* methods. It's common methods for getPrefix() methods.
*
* @param ListObjectsRequest
*
* @param ObjectListing
*/
private static HashMap<String, List<String>> prepareDataMap(ListObjectsRequest listObjectsRequest,
ObjectListing objectListing) {
HashMap<String, List<String>> prefixData = null;
try {
prefixData = new HashMap<String, List<String>>();
objectListing = s3Client.listObjects(listObjectsRequest);
List<String> commonPrefixes = objectListing.getCommonPrefixes();
if (commonPrefixes != null && commonPrefixes.size() != 0) {
prefixData.put(AWSCommonConstants.GET_FOLDER, commonPrefixes);
}
List<S3ObjectSummary> s3KeyList = new ArrayList<S3ObjectSummary>();
s3KeyList.addAll(objectListing.getObjectSummaries());
while (objectListing.isTruncated()) {
objectListing = s3Client.listNextBatchOfObjects(objectListing);
s3KeyList.addAll(objectListing.getObjectSummaries());
}
if (s3KeyList != null && s3KeyList.size() != 0) {
List<String> objectData = new ArrayList<String>();
for (S3ObjectSummary s3ObjectSummary : s3KeyList) {
objectData.add(s3ObjectSummary.getKey());
}
prefixData.put(AWSCommonConstants.GET_DATA, objectData);
}
} catch (AmazonS3Exception e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
return prefixData;
}
}
和测试类：
package com.elegant.amazon;
import java.util.HashMap;
import java.util.List;
import java.util.Scanner;
import com.amazonaws.services.s3.model.Bucket;
public class AmazonS3Test {
@SuppressWarnings("resource")
public static void main(String[] args) throws InterruptedException {
boolean yes = true;
do {
System.out.println("\n\n");
System.out.println("----------AMAZON-----------------------S3-------------------------TEST------------");
System.out.println(" 1 Get Buckets List");
System.out.println(" 2 Get First Prefix Of Bucket");
System.out.println(" 3 Get Next Prefix");
System.out.println(" 4 Exit");
System.out.println("----------AMAZON-----------------------S3-------------------------TEST------------");
System.out.println("\n\n");
int choice = (new Scanner(System.in)).nextInt();
switch (choice) {
case 1:
List<Bucket> buckets = AmazonS3Util.bucketList;
for (Bucket bucket : buckets) {
System.out.println(bucket.getName());
}
break;
case 2:
System.out.println("Enter Bucket Name");
String bucketName = (new Scanner(System.in)).nextLine();
HashMap<String, List<String>> prefixName = AmazonS3Util.getPrefix(bucketName);
if (prefixName.containsKey(AWSCommonConstants.GET_FOLDER)) {
List<String> prefixList = prefixName.get(AWSCommonConstants.GET_FOLDER);
for (String prefix : prefixList) {
System.out.println(prefix);
}
}
if (prefixName.containsKey(AWSCommonConstants.GET_DATA)) {
List<String> dataList = prefixName.get(AWSCommonConstants.GET_DATA);
for (String data : dataList) {
System.out.println(data);
}
}
break;
case 3:
System.out.println("Enter Bucket Name");
String bucketName1 = (new Scanner(System.in)).nextLine();
System.out.println("Enter Prefix Name");
String prefix1 = (new Scanner(System.in)).nextLine();
HashMap<String, List<String>> prefixName1 = AmazonS3Util.getPrefix(bucketName1, prefix1);
if (prefixName1.containsKey(AWSCommonConstants.GET_FOLDER)) {
List<String> prefixList = prefixName1.get(AWSCommonConstants.GET_FOLDER);
for (String prefix : prefixList) {
System.out.println(prefix);
}
}
if (prefixName1.containsKey(AWSCommonConstants.GET_DATA)) {
List<String> dataList = prefixName1.get(AWSCommonConstants.GET_DATA);
for (String data : dataList) {
System.out.println(data);
}
}
break;
case 4:
yes = false;
break;
default:
break;
}
} while (yes);
}
}
通过这个我们可以列出Amazon S3的目录结构