spring-integration Getting started with spring-integration Installation or Setup

Example

The best way to get started using Spring-Integration in your project is with a dependency management system, like gradle.

dependencies {
    compile 'org.springframework.integration:spring-integration-core:4.3.5.RELEASE'
}

Below is a very simple example using the gateway, service-activator message endpoints.

//these annotations will enable Spring integration and scan for components
@Configuration
@EnableIntegration
@IntegrationComponentScan
public class Application {
    //a channel has two ends, this Messaging Gateway is acting as input from one side of inChannel
    @MessagingGateway
    interface Greeting {
        @Gateway(requestChannel = "inChannel")
        String greet(String name);
    }

    @Component
    static class HelloMessageProvider {
        //a service activator act as a handler when message is received from inChannel, in this example, it is acting as the handler on the output side of inChannel
        @ServiceActivator(inputChannel = "inChannel")
        public String sayHello(String name) {
            return "Hi, " + name;
        }
    }

    @Bean
    MessageChannel inChannel() {
        return new DirectChannel();
    }

    public static void main(String[] args) {
        ApplicationContext context = new AnnotationConfigApplicationContext(Application.class);
        Greeting greeting = context.getBean(Greeting.class);
        //greeting.greet() send a message to the channel, which trigger service activitor to process the incoming message
        System.out.println(greeting.greet("Spring Integration!"));
    }
}

It will display the string Hi, Spring Integration! in the console.

Of course, Spring Integration also provides xml-style configuration. For the above example, you can write such following xml configuration file.

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:int="http://www.springframework.org/schema/integration"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/integration
        http://www.springframework.org/schema/integration/spring-integration.xsd">
    <int:gateway default-request-channel="inChannel"
                 service-interface="spring.integration.stackoverflow.getstarted.Application$Greeting"/>
    <int:channel id="inChannel"/>
    <int:service-activator input-channel="inChannel" method="sayHello">
        <bean class="spring.integration.stackoverflow.getstarted.Application$HelloMessageProvider"/>
    </int:service-activator>
</beans>

To run the application using the xml config file, you should change the code new AnnotationConfigApplicationContext(Application.class) in Application class to new ClassPathXmlApplicationContext("classpath:getstarted.xml"). And run this application again, you can see the same output.