Sending message attributes to an Amazon SQS queue

You can include structured metadata (such as timestamps, geospatial data, signatures, and identifiers) with messages using message attributes. For more information, see Amazon SQS message attributes.

Before you run the example code, make sure that you have set your AWS credentials. For more information, see Set up AWS Credentials and Region for Development in the AWS SDK for Java 2.x Developer Guide.

Defining attributes

To define an attribute for a message, add the following code, which uses the MessageAttributeValue data type. For more information, see Message attribute components and Message attribute data types.

The AWS SDK for Java automatically calculates the message body and message attribute checksums and compares them with the data that Amazon SQS returns. For more information, see the AWS SDK for Java 2.x Developer Guide and Calculating the MD5 message digest for message attributes for other programming languages.

String

This example defines a String attribute named Name with the value Jane.

final Map<String, MessageAttributeValue> messageAttributes = new HashMap<>();
messageAttributes.put("Name", new MessageAttributeValue()
.withDataType("String")
.withStringValue("Jane"));

Number

This example defines a Number attribute named AccurateWeight with the value 230.000000000000000001.

final Map<String, MessageAttributeValue> messageAttributes = new HashMap<>();
messageAttributes.put("AccurateWeight", new MessageAttributeValue()
.withDataType("Number")
.withStringValue("230.000000000000000001"));

Binary

This example defines a Binary attribute named ByteArray with the value of an uninitialized 10-byte array.

final Map<String, MessageAttributeValue> messageAttributes = new HashMap<>();
messageAttributes.put("ByteArray", new MessageAttributeValue()
.withDataType("Binary")
.withBinaryValue(ByteBuffer.wrap(new byte[10])));

String (custom)

This example defines the custom attribute String.EmployeeId named EmployeeId with the value ABC123456.

final Map<String, MessageAttributeValue> messageAttributes = new HashMap<>();
messageAttributes.put("EmployeeId", new MessageAttributeValue()
.withDataType("String.EmployeeId")
.withStringValue("ABC123456"));

Number (custom)

This example defines the custom attribute Number.AccountId named AccountId with the value 000123456.

final Map<String, MessageAttributeValue> messageAttributes = new HashMap<>();
messageAttributes.put("AccountId", new MessageAttributeValue()
.withDataType("Number.AccountId")
.withStringValue("000123456"));

Note

Because the base data type is Number, the ReceiveMessage method returns 123456.

Binary (custom)

This example defines the custom attribute Binary.JPEG named ApplicationIcon with the value of an uninitialized 10-byte array.

final Map<String, MessageAttributeValue> messageAttributes = new HashMap<>();
messageAttributes.put("ApplicationIcon", new MessageAttributeValue()
.withDataType("Binary.JPEG")
.withBinaryValue(ByteBuffer.wrap(new byte[10])));

Sending a message with attributes

This example adds the attributes to the SendMessageRequest before sending the message.

// Send a message with an attribute.
final SendMessageRequest sendMessageRequest = new SendMessageRequest();
sendMessageRequest.withMessageBody("This is my message text.");
sendMessageRequest.withQueueUrl(myQueueUrl);
sendMessageRequest.withMessageAttributes(messageAttributes);
sqs.sendMessage(sendMessageRequest);

Important

If you send a message to a First-In-First-Out (FIFO) queue, make sure that the sendMessage method executes after you provide the message group ID.

If you use the SendMessageBatch method instead of SendMessage, you must specify message attributes for each message in the batch.