Spring integration: MessagingTemplate demo

MessagingTemplate class provides lot of utility methods to work with requests and response over a channel.

 

Example

MessagingTemplate messaginTemplate = new MessagingTemplate();

Message<String> result = (Message<String>) messaginTemplate.sendAndReceive(inputChannel, message);

 

In the above snippet, I am using MessagingTemplate class to send a message over channel and receive the response.

 

Find the below working application.

 

Step 1: Create new maven project ‘messaging-template-demo’.

 

Step 2: Update pom.xml with maven dependencies.

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.sample.app</groupId>
	<artifactId>messaging-template-demo</artifactId>
	<version>1</version>

	<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-parent -->
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.4.0</version>
	</parent>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-integration</artifactId>
		</dependency>

	</dependencies>

</project>

Step 3: Create a package ‘com.sample.app.endpoints’ and define ConsumerEndpoint class.

 

ConsumerEndpoint.java

package com.sample.app.endpoints;

import org.springframework.integration.annotation.ServiceActivator;
import org.springframework.integration.support.MessageBuilder;
import org.springframework.messaging.Message;
import org.springframework.stereotype.Component;

@Component
public class ConsumerEndpoint {

	@ServiceActivator(inputChannel = "myChannel")
	public Message<String> consumeMessage(Message<String> message) {
		System.out.println("Received from Producer : " + message);
		return MessageBuilder.withPayload("Message Received").build();
	}

}

Step 4: Create a package ‘com.sample.app’ and define App class.

 

App.java

package com.sample.app;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.integration.channel.DirectChannel;
import org.springframework.integration.core.MessagingTemplate;
import org.springframework.integration.support.MessageBuilder;
import org.springframework.messaging.Message;

@SpringBootApplication
@Configuration
public class App {

	@Autowired
	@Qualifier("myChannel")
	private DirectChannel inputChannel;

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

	@Bean(name = "myChannel")
	public DirectChannel channel1() {
		DirectChannel channel = new DirectChannel();
		return channel;
	}

	@Bean
	public CommandLineRunner demo() {
		return (args) -> {
			Message<String> message = MessageBuilder.withPayload("Hello World").build();

			MessagingTemplate messaginTemplate = new MessagingTemplate();
			Message<String> result = (Message<String>) messaginTemplate.sendAndReceive(inputChannel, message);

			System.out.println("result = " + result);

		};
	}

}

Total project structure looks like below.

Run App.java, you will see below messages in console.

Received from Producer : GenericMessage [payload=Hello World, headers={replyChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@6a1d204a, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@6a1d204a, id=62f4905f-8c2f-26a5-9c65-4b3e58bf5de9, timestamp=1617378622457}]
result = GenericMessage [payload=Message Received, headers={id=0d7525a2-fa88-7600-5e46-f18fb37a5ed8, timestamp=1617378622462}]

You can download complete working application from below link.

https://github.com/harikrishna553/springboot/tree/master/spring-integration/messaging-template-demo

 

 

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