Spring Integration — Message

In this example, we’ll use Spring Integration basics — Message.

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>

   <groupId>com.oreilly.integration</groupId>
   <artifactId>spring-integration</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <packaging>jar</packaging>

   <name>spring-integration</name>
   <description>Demo project for Spring Boot</description>

   <parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>2.6.1</version>
      <relativePath/> <!-- lookup parent from repository -->
   </parent>

   <properties>
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
      <java.version>1.8</java.version>
   </properties>

   <dependencies>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-integration</artifactId>
      </dependency>
      
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-test</artifactId>
         <scope>test</scope>
      </dependency>
   </dependencies>
   
   <build>
      <plugins>
         <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
         </plugin>
      </plugins>
   </build>
</project>

PrintService.java

import java.util.Map.Entry;

import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHeaders;

public class PrintService {

   public void print(Message<String> message){
      MessageHeaders headers = message.getHeaders();
      
      for(Entry<String,Object> entry:headers.entrySet()){
         System.out.println("Key >> "+ entry.getKey()+":: Value >> "+ entry.getValue());
      }
      
      System.out.println(message.getPayload());
   }
}

MainApp.java

import java.util.HashMap;
import java.util.Map;

import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.ImportResource;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHeaders;
import org.springframework.messaging.support.GenericMessage;
import org.springframework.messaging.support.MessageBuilder;

@SpringBootApplication
@Configuration
@ImportResource("integration-context.xml")
public class SpringIntegrationApplication implements ApplicationRunner {

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

   @Override
   public void run(ApplicationArguments arg0) throws Exception {

      Message<String> message = MessageBuilder
            .withPayload("Hello World, from the builder pattern")
            .setHeader("newHeader", "newHeaderValue")
            .build();

      PrintService service = new PrintService();
      service.print(message);
   }
}

integration-context.xml

<?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-4.2.xsd">


</beans>

Output —

2021–12–12 20:59:47.852 INFO 24232 — — [ main] c.o.i.SpringIntegrationApplication : Started SpringIntegrationApplication in 0.984 seconds (JVM running for 1.686)
Key >> newHeader:: Value >> newHeaderValue
Key >> id:: Value >> 55bc245c-5f54-af36-c8d7-ce742e42627f
Key >> timestamp:: Value >> 1639322987855
Hello World, from the builder pattern
2021–12–12 20:59:47.858 INFO 24232 — — [ionShutdownHook] o.s.i.endpoint.EventDrivenConsumer : Removing {logging-channel-adapter:_org.springframework.integration.errorLogger} as a subscriber to the