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Generate Pre-signed Object URL using AWS SDK for Java

The following tasks guide you through using the Java classes to generate a pre-signed URL.

Downloading Objects

Create an instance of the AmazonS3 class by providing your AWS credentials.

These credentials are used in creating a signature for authentication when you generate a pre-signed URL.

Execute the AmazonS3.generatePresignedUrl method to generate a pre-signed URL.

You provide information including a bucket name, an object key, and an expiration date by creating an instance of the GeneratePresignedUrlRequest class.

The following Java code sample demonstrates the preceding tasks.

AWSCredentials myCredentials = new BasicAWSCredentials(
                                myAccessKeyID, mySecretKey);
AmazonS3 s3Client = new AmazonS3Client(myCredentials); 
       
java.util.Date expiration = new java.util.Date();
long msec = expiration.getTime();
msec += 1000 * 60 * 60; // 1 hour.
expiration.setTime(msec);
             
GeneratePresignedUrlRequest generatePresignedUrlRequest = 
              new GeneratePresignedUrlRequest(bucketName, objectKey);
generatePresignedUrlRequest.setMethod(HttpMethod.GET); // Default.
generatePresignedUrlRequest.setExpiration(expiration);
             
URL s = s3client.generatePresignedUrl(generatePresignedUrlRequest);

Example

The following Java code example generates a pre-signed URL that you can give to others so that they can retrieve the object. For instructions about how to create and test a working sample, see Testing the Java Code Examples

import java.io.IOException;
import java.net.URL;

import com.amazonaws.AmazonClientException;
import com.amazonaws.AmazonServiceException;
import com.amazonaws.HttpMethod;
import com.amazonaws.auth.PropertiesCredentials;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.GeneratePresignedUrlRequest;
import java.net.*;
import java.io.*;

public class S3Sample {
	private static String bucketName = "*** Provide a bucket name ***"; 
	private static String objectKey = "*** Provide an object key ***";

	public static void main(String[] args) throws IOException {
		AmazonS3 s3client = new AmazonS3Client(new PropertiesCredentials(
			S3Sample.class.getResourceAsStream("AwsCredentials.properties")));

		try {
			System.out.println("Generating pre-signed URL.");
			java.util.Date expiration = new java.util.Date();
			long milliSeconds = expiration.getTime();
			milliSeconds += 1000 * 60 * 60; // Add 1 hour.
			expiration.setTime(milliSeconds);

			GeneratePresignedUrlRequest generatePresignedUrlRequest = 
				    new GeneratePresignedUrlRequest(bucketName, objectKey);
			generatePresignedUrlRequest.setMethod(HttpMethod.GET); 
			generatePresignedUrlRequest.setExpiration(expiration);

			URL url = s3client.generatePresignedUrl(generatePresignedUrlRequest); 

			System.out.println("Pre-Signed URL = " + url.toString());
		} catch (AmazonServiceException exception) {
			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: " + exception.getMessage());
			System.out.println("HTTP  Code: "    + exception.getStatusCode());
			System.out.println("AWS Error Code:" + exception.getErrorCode());
			System.out.println("Error Type:    " + exception.getErrorType());
			System.out.println("Request ID:    " + exception.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());
		}
	}
}

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