Wednesday, February 12, 2014

Spring Integration Standalone application with Spring Boot

I had earlier blogged about a way to write a standalone Spring Integration application. Spring Boot makes creating this standalone application much simpler.

The simple flow was to poll the USGS service providing information about the earthquake activity around the world and to log this information. The flow described using Spring Integration is the following:

 <int:inbound-channel-adapter channel="" expression="''">
  <int:poller fixed-delay="60000"></int:poller>
 <int:channel id="">
  <int:queue capacity="10"/>

 <int:channel id=""></int:channel> 

 <int-http:outbound-gateway id="quakerHttpGateway"
 <int:logging-channel-adapter id="messageLogger" log-full-message="true" channel="" level="ERROR">
  <int:poller fixed-delay="5000" ></int:poller>

Pre-boot, the way to write a main program to start this flow would have been along these lines:

package standalone;
public class Main {
 public static void main(String[] args) {
  ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("classpath:/httpgateway.xml");

With Spring-boot however the configuration is IMHO simpler:

package standalone;

import org.springframework.boot.SpringApplication;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.ImportResource;

public class Main {

 public static void main(String[] args) {, args);

And with this change, along with the spring-boot-maven-plugin plugin, the application can be started up this way:

mvn spring-boot:run

I had a very small hand in fixing this start-up script by contributing a change to the plugin to start-up the application without needing to manually run the compilation step first.

Even better, the spring-boot-maven-plugin provides tools to package the entire application into a executable jar which gets triggered during the package phase, along the lines of shade plugin:

mvn package 

and the executable jar run this way:

java -jar target/si-standalone-sample-1.0-SNAPSHOT.jar

An updated project with this change is available at this github location -

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