Get an Object Using the AWS SDK for Java

When you download an object through the AWS SDK for Java, Amazon S3 returns all of the object's metadata and an input stream from which to read the object's contents.

To retrieve an object, you do the following:

• Execute the AmazonS3Client.getObject() method, providing the bucket name and object key in the request.
• Execute one of the S3Object instance methods to process the input stream.

Note
Your network connection remains open until you read all of the data or close the input stream. We recommend that you read the content of the stream as quickly as possible.

The following are some variations you might use:

• Instead of reading the entire object, you can read only a portion of the object data by specifying the byte range that you want in the request.
• You can optionally override the response header values (see Getting Objects) by using a ResponseHeaderOverrides object and setting the corresponding request property. For example, you can use this feature to indicate that the object should be downloaded into a file with a different file name than the object key name.

The following example retrieves an object from an Amazon S3 bucket three ways: first, as a complete object, then as a range of bytes from the object, then as a complete object with overridden response header values. For more information about getting objects from Amazon S3, see GET Object. For instructions on creating and testing a working sample, see Testing the Amazon S3 Java Code Examples.

import com.amazonaws.AmazonServiceException;

import com.amazonaws.SdkClientException;

import com.amazonaws.auth.profile.ProfileCredentialsProvider;

import com.amazonaws.regions.Regions;

import com.amazonaws.services.s3.AmazonS3;

import com.amazonaws.services.s3.AmazonS3ClientBuilder;

import com.amazonaws.services.s3.model.GetObjectRequest;

import com.amazonaws.services.s3.model.ResponseHeaderOverrides;

import com.amazonaws.services.s3.model.S3Object;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

public class GetObject {

public static void main(String[] args) throws IOException {

Regions clientRegion = Regions.DEFAULT_REGION;

String bucketName = "*** Bucket name ***";

String key = "*** Object key ***";

S3Object fullObject = null, objectPortion = null, headerOverrideObject = null;

try {

AmazonS3 s3Client = AmazonS3ClientBuilder.standard()

.withRegion(clientRegion)

.withCredentials(new ProfileCredentialsProvider())

.build();

// Get an object and print its contents.

System.out.println("Downloading an object");

fullObject = s3Client.getObject(new GetObjectRequest(bucketName, key));

System.out.println("Content-Type: " + fullObject.getObjectMetadata().getContentType());

System.out.println("Content: ");

displayTextInputStream(fullObject.getObjectContent());

// Get a range of bytes from an object and print the bytes.

GetObjectRequest rangeObjectRequest = new GetObjectRequest(bucketName, key)

.withRange(0, 9);

objectPortion = s3Client.getObject(rangeObjectRequest);

System.out.println("Printing bytes retrieved.");

displayTextInputStream(objectPortion.getObjectContent());

// Get an entire object, overriding the specified response headers, and print the object's content.

ResponseHeaderOverrides headerOverrides = new ResponseHeaderOverrides()

.withCacheControl("No-cache")

.withContentDisposition("attachment; filename=example.txt");

GetObjectRequest getObjectRequestHeaderOverride = new GetObjectRequest(bucketName, key)

.withResponseHeaders(headerOverrides);

headerOverrideObject = s3Client.getObject(getObjectRequestHeaderOverride);

displayTextInputStream(headerOverrideObject.getObjectContent());

} catch (AmazonServiceException e) {

// The call was transmitted successfully, but Amazon S3 couldn't process

// it, so it returned an error response.

e.printStackTrace();

} catch (SdkClientException e) {

// Amazon S3 couldn't be contacted for a response, or the client

// couldn't parse the response from Amazon S3.

e.printStackTrace();

} finally {

// To ensure that the network connection doesn't remain open, close any open input streams.

if (fullObject != null) {

fullObject.close();

}

if (objectPortion != null) {

objectPortion.close();

}

if (headerOverrideObject != null) {

headerOverrideObject.close();

}

}

}

private static void displayTextInputStream(InputStream input) throws IOException {

// Read the text input stream one line at a time and display each line.

BufferedReader reader = new BufferedReader(new InputStreamReader(input));

String line = null;

while ((line = reader.readLine()) != null) {

System.out.println(line);

}

System.out.println();

}

}