How to subcribe to Spring Boot JMS topic from other app - spring-boot

Question

I have 2 applications, the first app starts a ActiveMQ broker ( https://spring.io/guides/gs/messaging-jms/ ).
At the second app I want to subcribe a topic from the first app.
How can I do this without starting a ActiveMQ Server?
Possible solution:
Server Application Project
import java.time.LocalDateTime;
import javax.jms.ConnectionFactory;
import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.broker.BrokerService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.jms.annotation.EnableJms;
import org.springframework.jms.config.DefaultJmsListenerContainerFactory;
import org.springframework.jms.core.JmsTemplate;
import org.springframework.jms.support.converter.MappingJackson2MessageConverter;
import org.springframework.jms.support.converter.MessageConverter;
import org.springframework.jms.support.converter.MessageType;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.ui.ModelMap;
#SpringBootApplication
#EnableJms
#EnableScheduling
public class JsmServerApplication {
#Autowired
JmsTemplate jmsTemplate;
#Bean
public BrokerService broker() throws Exception {
BrokerService ret = new BrokerService();
ret.addConnector("tcp://0.0.0.0:4444"); // allow remote connections
ret.setBrokerName("primary-broker");
ret.setUseJmx(true);
return ret;
}
#Bean
public ConnectionFactory connectionFactory() {
return new ActiveMQConnectionFactory("tcp://localhost:4444");
}
#Bean
public DefaultJmsListenerContainerFactory jmsListenerContainerFactory(ConnectionFactory connectionFactory) {
DefaultJmsListenerContainerFactory factory = new DefaultJmsListenerContainerFactory();
factory.setConnectionFactory(connectionFactory);
factory.setMessageConverter(jacksonJmsMessageConverter());
return factory;
}
#Bean
public MessageConverter jacksonJmsMessageConverter() {
MappingJackson2MessageConverter converter = new MappingJackson2MessageConverter();
converter.setTargetType(MessageType.TEXT);
converter.setTypeIdPropertyName("_type");
return converter;
}
public static void main(String[] args) {
SpringApplication.run(JsmServerApplication.class, args);
}
#Scheduled(cron = "*/5 * * * * ?")
public void run() {
ModelMap msg = new ModelMap("now", LocalDateTime.now().toString());
System.out.println("Sending: " + msg);
jmsTemplate.convertAndSend("messages", msg);
}
}
Client Application Project
import javax.jms.ConnectionFactory;
import org.apache.activemq.ActiveMQConnectionFactory;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.jms.annotation.EnableJms;
import org.springframework.jms.annotation.JmsListener;
import org.springframework.jms.config.DefaultJmsListenerContainerFactory;
import org.springframework.jms.support.converter.MappingJackson2MessageConverter;
import org.springframework.jms.support.converter.MessageConverter;
import org.springframework.jms.support.converter.MessageType;
import org.springframework.ui.ModelMap;
#SpringBootApplication
#EnableJms
public class JsmClientApplication {
#Bean
public ConnectionFactory connectionFactory() {
return new ActiveMQConnectionFactory("tcp://localhost:4444");
}
#Bean
public DefaultJmsListenerContainerFactory jmsListenerContainerFactory(ConnectionFactory connectionFactory) {
DefaultJmsListenerContainerFactory factory = new DefaultJmsListenerContainerFactory();
factory.setConnectionFactory(connectionFactory);
factory.setMessageConverter(jacksonJmsMessageConverter());
return factory;
}
#Bean
public MessageConverter jacksonJmsMessageConverter() {
MappingJackson2MessageConverter converter = new MappingJackson2MessageConverter();
converter.setTargetType(MessageType.TEXT);
converter.setTypeIdPropertyName("_type");
return converter;
}
#JmsListener(destination = "messages", containerFactory = "jmsListenerContainerFactory")
public void msg(ModelMap msg) {
System.out.println(msg);
}
public static void main(String[] args) {
SpringApplication.run(JsmClientApplication.class, args);
}
}
Is it a correct approch?
Solved with this:
http://javasampleapproach.com/java-integration/activemq-work-spring-jms-activemq-topic-publisher-subcribers-pattern-using-springboot

Answer 1

You can use the MessageConsumer to consume the data like the code below
public static void main(String[] args) throws JMSException {
// Getting JMS connection from the server
ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(url);
Connection connection = connectionFactory.createConnection();
connection.start();
Session session = connection.createSession(false,
Session.AUTO_ACKNOWLEDGE);
Topic topic = session.createTopic("topic");
MessageConsumer consumer = session.createConsumer(topic);
MessageListener listner = new MessageListener() {
public void onMessage(Message message) {
try {
//do operations
} catch (JMSException e) {
}
}
};
consumer.setMessageListener(listner);
connection.close();
}
Since you are using the ActiveMQConnectionFactory, you can set the broker as below
BrokerService broker = new BrokerService();
broker.addConnector("tcp://localhost:4444);
broker.setPersistent(false);
ActiveMQConnectionFactory cf = new ActiveMQConnectionFactory("vm://localhost?broker.persistent=false");
If you do not have any restrictions in not using ActiveMQ, You can use Kafka for doing the same. Kafka provides you a highly scalable and distributed Message Bus with simple API.
https://kafka.apache.org/quickstart
I am not sure about the constraints but I just wanted to give you a feel of Kafka. However, the above code should help you in understanding the concept of subscribing and consuming messages from a topic.

Answer 2

See this answer for how to listen on a tcp port instead of the vm:// transport.