Chapter 3. Getting started

This chapter guides you through a simple exercise to help you get started using AMQ Spring Boot Starter.

3.1. Prerequisites

To build the example, Maven must be configured to use the Red Hat repository.

3.2. Preparing the broker

The example programs require a running broker with a queue named example. Follow these steps to define the queue and start the broker:

Procedure

  1. Install the broker.
  2. Create a broker instance. Enable anonymous access.
  3. Start the broker instance and check the console for any critical errors logged during startup.

    $ <broker-instance-dir>/bin/artemis run
    ...
    14:43:20,158 INFO  [org.apache.activemq.artemis.integration.bootstrap] AMQ101000: Starting ActiveMQ Artemis Server
    ...
    15:01:39,686 INFO  [org.apache.activemq.artemis.core.server] AMQ221020: Started Acceptor at 0.0.0.0:5672 for protocols [AMQP]
    ...
    15:01:39,691 INFO  [org.apache.activemq.artemis.core.server] AMQ221007: Server is now live
  4. Use the artemis queue command to create a queue called example.

    <broker-instance-dir>/bin/artemis queue create --name example --auto-create-address --anycast

    You are prompted to answer a series of questions. For yes or no questions, type N. Otherwise, press Enter to accept the default value.

3.3. Hello World

This example sends a greeting to a queue called example and then receives it back.

Example: Sending and receiving "Hello World!" - HelloWorld.java

package net.example;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.jms.annotation.EnableJms;
import org.springframework.jms.annotation.JmsListener;
import org.springframework.jms.core.JmsTemplate;

@EnableJms
@SpringBootApplication
public class HelloWorld implements CommandLineRunner {
    @Autowired
    private JmsTemplate jmsTemplate;

    public static void main(String[] args) {
        SpringApplication.run(HelloWorld.class, args);
    }

    @Override
    public void run(String... strings) throws Exception {
        sendMessage("Hello World!");
    }

    public void sendMessage(String text) {
        System.out.println(String.format("Sending '%s'", text));
        this.jmsTemplate.convertAndSend("example", text);
    }

    @JmsListener(destination = "example")
    public void receiveMessage(String text) {
        System.out.println(String.format("Received '%s'", text));
    }
}

Running the example

To compile and run the example program, use the following procedure:

Procedure

  1. Create a new project directory. This is referred to as <project-dir> in the steps that follow.
  2. Copy the example listing to the following location:

    <project-dir>/src/main/java/net/example/HelloWorld.java
  3. Use a text editor to create a new <project-dir>/pom.xml file. Add the following XML to it:

    <project>
      <modelVersion>4.0.0</modelVersion>
    
      <groupId>net.example</groupId>
      <artifactId>example</artifactId>
      <version>1.0.0-SNAPSHOT</version>
    
      <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.5.RELEASE</version>
      </parent>
    
      <dependencies>
        <dependency>
          <groupId>org.amqphub.spring</groupId>
          <artifactId>amqp-10-jms-spring-boot-starter</artifactId>
          <version>2.2.2.redhat-00002</version>
        </dependency>
      </dependencies>
    
      <build>
        <plugins>
          <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
          </plugin>
        </plugins>
      </build>
    </project>
  4. Change to the project directory and use the mvn command to compile the program.

    mvn clean package
  5. Use the java command to run the program.

    java -jar target/example-1.0.0-SNAPSHOT.jar

    Running the Hello World example results in the following console output:

    $ java -jar target/example-1.0.0-SNAPSHOT.jar
    
      .   ____          _            __ _ _
     /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
    ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
     \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
      '  |____| .__|_| |_|_| |_\__, | / / / /
     =========|_|==============|___/=/_/_/_/
     :: Spring Boot ::        (v2.0.5.RELEASE)
    
    [...]
    2018-11-05 16:21:09.849  INFO 14805 --- [main] net.example.HelloWorld: Started HelloWorld in 1.074 seconds (JVM running for 1.38)
    Sending 'Hello World!'
    Received 'Hello World!'

3.4. Additional examples

More example programs are available from the AMQP 1.0 JMS Spring Boot project and the Spring project.