Amazon s3 upload java

Performing Operations on Amazon S3 Objects

An Amazon S3 object represents a file or collection of data. Every object must reside within a bucket.

Note

These code examples assume that you understand the material in Using the AWS SDK for Java and have configured default AWS credentials using the information in Set up AWS Credentials and Region for Development.

Topics

Upload an Object

Use the AmazonS3 client’s putObject method, supplying a bucket name, key name, and file to upload. The bucket must exist, or an error will result.

import com.amazonaws.AmazonServiceException; import com.amazonaws.regions.Regions; import com.amazonaws.services.s3.AmazonS3;

System.out.format("Uploading %s to S3 bucket %s. \n", file_path, bucket_name); final AmazonS3 s3 = AmazonS3ClientBuilder.standard().withRegion(Regions.DEFAULT_REGION).build(); try  s3.putObject(bucket_name, key_name, new File(file_path)); > catch (AmazonServiceException e)  System.err.println(e.getErrorMessage()); System.exit(1); >

List Objects

To get a list of objects within a bucket, use the AmazonS3 client’s listObjects method, supplying the name of a bucket.

The listObjects method returns an ObjectListing object that provides information about the objects in the bucket. To list the object names (keys), use the getObjectSummaries method to get a List of S3ObjectSummary objects, each of which represents a single object in the bucket. Then call its getKey method to retrieve the object’s name.

import com.amazonaws.regions.Regions; import com.amazonaws.services.s3.AmazonS3; import com.amazonaws.services.s3.AmazonS3ClientBuilder; import com.amazonaws.services.s3.model.ListObjectsV2Result; import com.amazonaws.services.s3.model.S3ObjectSummary;

System.out.format("Objects in S3 bucket %s:\n", bucket_name); final AmazonS3 s3 = AmazonS3ClientBuilder.standard().withRegion(Regions.DEFAULT_REGION).build(); ListObjectsV2Result result = s3.listObjectsV2(bucket_name); List objects = result.getObjectSummaries(); for (S3ObjectSummary os : objects)  System.out.println("* " + os.getKey()); >

Download an Object

Use the AmazonS3 client’s getObject method, passing it the name of a bucket and object to download. If successful, the method returns an S3Object. The specified bucket and object key must exist, or an error will result.

You can get the object’s contents by calling getObjectContent on the S3Object . This returns an S3ObjectInputStream that behaves as a standard Java InputStream object.

The following example downloads an object from S3 and saves its contents to a file (using the same name as the object’s key).

import com.amazonaws.AmazonServiceException; import com.amazonaws.regions.Regions; import com.amazonaws.services.s3.AmazonS3; import com.amazonaws.services.s3.AmazonS3ClientBuilder; import com.amazonaws.services.s3.model.S3Object; import com.amazonaws.services.s3.model.S3ObjectInputStream; import java.io.File;

System.out.format("Downloading %s from S3 bucket %s. \n", key_name, bucket_name); final AmazonS3 s3 = AmazonS3ClientBuilder.standard().withRegion(Regions.DEFAULT_REGION).build(); try  S3Object o = s3.getObject(bucket_name, key_name); S3ObjectInputStream s3is = o.getObjectContent(); FileOutputStream fos = new FileOutputStream(new File(key_name)); byte[] read_buf = new byte[1024]; int read_len = 0; while ((read_len = s3is.read(read_buf)) > 0)  fos.write(read_buf, 0, read_len); > s3is.close(); fos.close(); > catch (AmazonServiceException e)  System.err.println(e.getErrorMessage()); System.exit(1); > catch (FileNotFoundException e)  System.err.println(e.getMessage()); System.exit(1); > catch (IOException e)  System.err.println(e.getMessage()); System.exit(1); >

Copy, Move, or Rename Objects

You can copy an object from one bucket to another by using the AmazonS3 client’s copyObject method. It takes the name of the bucket to copy from, the object to copy, and the destination bucket name.

import com.amazonaws.AmazonServiceException; import com.amazonaws.regions.Regions;

try  s3.copyObject(from_bucket, object_key, to_bucket, object_key); > catch (AmazonServiceException e)  System.err.println(e.getErrorMessage()); System.exit(1); > System.out.println("Done!");

Note

You can use copyObject with deleteObject to move or rename an object, by first copying the object to a new name (you can use the same bucket as both the source and destination) and then deleting the object from its old location.

Delete an Object

Use the AmazonS3 client’s deleteObject method, passing it the name of a bucket and object to delete. The specified bucket and object key must exist, or an error will result.

import com.amazonaws.AmazonServiceException; import com.amazonaws.regions.Regions;

final AmazonS3 s3 = AmazonS3ClientBuilder.standard().withRegion(Regions.DEFAULT_REGION).build(); try  s3.deleteObject(bucket_name, object_key); > catch (AmazonServiceException e)  System.err.println(e.getErrorMessage()); System.exit(1); >

Delete Multiple Objects at Once

Using the AmazonS3 client’s deleteObjects method, you can delete multiple objects from the same bucket by passing their names to the link:sdk-for-java/v1/reference/com/amazonaws/services/s3/model/DeleteObjectsRequest.html method.

import com.amazonaws.AmazonServiceException; import com.amazonaws.regions.Regions; import com.amazonaws.services.s3.AmazonS3;

final AmazonS3 s3 = AmazonS3ClientBuilder.standard().withRegion(Regions.DEFAULT_REGION).build(); try  DeleteObjectsRequest dor = new DeleteObjectsRequest(bucket_name) .withKeys(object_keys); s3.deleteObjects(dor); > catch (AmazonServiceException e)  System.err.println(e.getErrorMessage()); System.exit(1); >

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