Setup
The following examples may require some or all of the following java classes to be imported:
import java.io.ByteArrayInputStream;
import java.io.File;
import java.util.List;
import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.util.StringUtils;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.Bucket;
import com.amazonaws.services.s3.model.CannedAccessControlList;
import com.amazonaws.services.s3.model.GeneratePresignedUrlRequest;
import com.amazonaws.services.s3.model.GetObjectRequest;
import com.amazonaws.services.s3.model.ObjectListing;
import com.amazonaws.services.s3.model.ObjectMetadata;
import com.amazonaws.services.s3.model.S3ObjectSummary;
Creating a Connection
This creates a connection so that you can interact with the server.
String accessKey = "insert your access key here!";
String secretKey = "insert your secret key here!";
AWSCredentials credentials = new BasicAWSCredentials(accessKey, secretKey);
AmazonS3 conn = new AmazonS3Client(credentials);
conn.setEndpoint("objects-us-west-1.dream.io");
Listing Owned Buckets
This gets a list of Buckets that you own. This also prints out the bucket name and creation date of each bucket.
List<Bucket> buckets = conn.listBuckets();
for (Bucket bucket : buckets) {
System.out.println(bucket.getName() + "\t" +
StringUtils.fromDate(bucket.getCreationDate()));
}
The output will look something like this:
mahbuckat1 2011-04-21T18:05:39.000Z
mahbuckat2 2011-04-21T18:05:48.000Z
mahbuckat3 2011-04-21T18:07:18.000Z
Creating a Bucket
This creates a new bucket called my-new-bucket
Bucket bucket = conn.createBucket("my-new-bucket");
Listing a Bucket’s Content
This gets a list of objects in the bucket. This also prints out each object’s name, the file size, and last modified date.
ObjectListing objects = conn.listObjects(bucket.getName());
do {
for (S3ObjectSummary objectSummary : objects.getObjectSummaries()) {
System.out.println(objectSummary.getKey() + "\t" +
ObjectSummary.getSize() + "\t" +
StringUtils.fromDate(objectSummary.getLastModified()));
}
objects = conn.listNextBatchOfObjects(objects);
} while (objects.isTruncated());
The output will look something like this:
myphoto1.jpg 251262 2011-08-08T21:35:48.000Z
myphoto2.jpg 262518 2011-08-08T21:38:01.000Z
Deleting a Bucket
Note
The Bucket must be empty! Otherwise it won’t work!
conn.deleteBucket(bucket.getName());
Forced Delete for Non-empty Buckets
Attention
not available
Creating an Object
This creates a file hello.txt with the string "Hello World!"
ByteArrayInputStream input = new ByteArrayInputStream("Hello World!".getBytes());
conn.putObject(bucket.getName(), "hello.txt", input, new ObjectMetadata());
Change an Object’s ACL
This makes the object hello.txt to be publicly readable, and
secret_plans.txt to be private.
conn.setObjectAcl(bucket.getName(), "hello.txt", CannedAccessControlList.PublicRead);
conn.setObjectAcl(bucket.getName(), "secret_plans.txt", CannedAccessControlList.Private);
Download an Object (to a file)
This downloads the object perl_poetry.pdf and saves it in
/home/larry/documents
conn.getObject(
new GetObjectRequest(bucket.getName(), "perl_poetry.pdf"),
new File("/home/larry/documents/perl_poetry.pdf")
);
Delete an Object
This deletes the object goodbye.txt
conn.deleteObject(bucket.getName(), "goodbye.txt");
Generate Object Download URLs (signed and unsigned)
This generates an unsigned download URL for hello.txt. This works
because we made hello.txt public by setting the ACL above.
This then generates a signed download URL for secret_plans.txt that
will work for 1 hour. Signed download URLs will work for the time
period even if the object is private (when the time period is up, the
URL will stop working).
Note
The java library does not have a method for generating unsigned URLs, so the example below just generates a signed URL.
GeneratePresignedUrlRequest request = new GeneratePresignedUrlRequest(bucket.getName(), "secret_plans.txt");
System.out.println(conn.generatePresignedUrl(request));
The output will look something like this:
https://my-bucket-name.objects-us-west-1.dream.io/secret_plans.txt?Signature=XXXXXXXXXXXXXXXXXXXXXXXXXXX&Expires=1316027075&AWSAccessKeyId=XXXXXXXXXXXXXXXXXXX
