The JmsTemplate contains many convenience methods to send a message. Send methods specify the destination by using a jakarta.jms.Destination object, and others specify the destination by using a String in a JNDI lookup. The send method that takes no destination argument uses the default destination.spring-doc.cn

The following example uses the MessageCreator callback to create a text message from the supplied Session object:spring-doc.cn

import jakarta.jms.ConnectionFactory;
import jakarta.jms.JMSException;
import jakarta.jms.Message;
import jakarta.jms.Queue;
import jakarta.jms.Session;

import org.springframework.jms.core.MessageCreator;
import org.springframework.jms.core.JmsTemplate;

public class JmsQueueSender {

	private JmsTemplate jmsTemplate;
	private Queue queue;

	public void setConnectionFactory(ConnectionFactory cf) {
		this.jmsTemplate = new JmsTemplate(cf);
	}

	public void setQueue(Queue queue) {
		this.queue = queue;
	}

	public void simpleSend() {
		this.jmsTemplate.send(this.queue, new MessageCreator() {
			public Message createMessage(Session session) throws JMSException {
				return session.createTextMessage("hello queue world");
			}
		});
	}
}

In the preceding example, the JmsTemplate is constructed by passing a reference to a ConnectionFactory. As an alternative, a zero-argument constructor and connectionFactory is provided and can be used for constructing the instance in JavaBean style (using a BeanFactory or plain Java code). Alternatively, consider deriving from Spring’s JmsGatewaySupport convenience base class, which provides pre-built bean properties for JMS configuration.spring-doc.cn

The send(String destinationName, MessageCreator creator) method lets you send a message by using the string name of the destination. If these names are registered in JNDI, you should set the destinationResolver property of the template to an instance of JndiDestinationResolver.spring-doc.cn

If you created the JmsTemplate and specified a default destination, the send(MessageCreator c) sends a message to that destination.spring-doc.cn

Using Message Converters

To facilitate the sending of domain model objects, the JmsTemplate has various send methods that take a Java object as an argument for a message’s data content. The overloaded methods convertAndSend() and receiveAndConvert() methods in JmsTemplate delegate the conversion process to an instance of the MessageConverter interface. This interface defines a simple contract to convert between Java objects and JMS messages. The default implementation (SimpleMessageConverter) supports conversion between String and TextMessage, byte[] and BytesMessage, and java.util.Map and MapMessage. By using the converter, you and your application code can focus on the business object that is being sent or received through JMS and not be concerned with the details of how it is represented as a JMS message.spring-doc.cn

The sandbox currently includes a MapMessageConverter, which uses reflection to convert between a JavaBean and a MapMessage. Other popular implementation choices you might implement yourself are converters that use an existing XML marshalling package (such as JAXB or XStream) to create a TextMessage that represents the object.spring-doc.cn

To accommodate the setting of a message’s properties, headers, and body that can not be generically encapsulated inside a converter class, the MessagePostProcessor interface gives you access to the message after it has been converted but before it is sent. The following example shows how to modify a message header and a property after a java.util.Map is converted to a message:spring-doc.cn

public void sendWithConversion() {
	Map map = new HashMap();
	map.put("Name", "Mark");
	map.put("Age", new Integer(47));
	jmsTemplate.convertAndSend("testQueue", map, new MessagePostProcessor() {
		public Message postProcessMessage(Message message) throws JMSException {
			message.setIntProperty("AccountID", 1234);
			message.setJMSCorrelationID("123-00001");
			return message;
		}
	});
}

This results in a message of the following form:spring-doc.cn

MapMessage={
	Header={
		... standard headers ...
		CorrelationID={123-00001}
	}
	Properties={
		AccountID={Integer:1234}
	}
	Fields={
		Name={String:Mark}
		Age={Integer:47}
	}
}

Using SessionCallback and ProducerCallback

While the send operations cover many common usage scenarios, you might sometimes want to perform multiple operations on a JMS Session or MessageProducer. The SessionCallback and ProducerCallback expose the JMS Session and Session / MessageProducer pair, respectively. The execute() methods on JmsTemplate run these callback methods.spring-doc.cn