Spring Integration

https://github.com/spring-boot-tutorials/spring-hateoas

In this article we will configure Spring Integration.

Create Initial Code Base

Go to https://start.spring.io/
Add the following dependencies:
- spring-boot-starter-integration
- spring-boot-starter-web
- spring-integration-file
- spring-integration-http
- lombok
Click Generate

Dependencies

Dependencies used in pom.xml

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-integration</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.integration</groupId>
    <artifactId>spring-integration-file</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.integration</groupId>
    <artifactId>spring-integration-http</artifactId>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>

Configuration

Let’s create a new file src/main/java/com/example/spring_integration/config/DefaultConfiguration.java

@Configuration
@EnableIntegration
public class DefaultConfiguration {

    public String INPUT_DIR = "the_source_dir";
    public String OUTPUT_DIR = "the_dest_dir";
    public String FILE_PATTERN = "*.mpeg";

    @Bean
    public MessageChannel fileChannel() {
        return new DirectChannel();
    }

    @Bean
    @InboundChannelAdapter(value = "fileChannel", poller = @Poller(fixedDelay = "1000"))
    public MessageSource<File> fileReadingMessageSource() {
        FileReadingMessageSource sourceReader= new FileReadingMessageSource();
        sourceReader.setDirectory(new File(INPUT_DIR));
//        sourceReader.setFilter(new SimplePatternFileListFilter(FILE_PATTERN));
        return sourceReader;
    }

    @Bean
    @ServiceActivator(inputChannel= "fileChannel")
    public MessageHandler fileWritingMessageHandler() {
        FileWritingMessageHandler handler = new FileWritingMessageHandler(new File(OUTPUT_DIR));
        handler.setFileExistsMode(FileExistsMode.REPLACE);
        handler.setExpectReply(false);
        return handler;
    }
}

Main

Modify MainApplication.java:

@SpringBootApplication
public class SpringIntegrationApplication {

    public static void main(String[] args) {
            AbstractApplicationContext context = new AnnotationConfigApplicationContext(SpringIntegrationApplication.class);
            context.registerShutdownHook();

            Scanner scanner = new Scanner(System.in);
            System.out.print("Please enter q and press <enter> to exit the program: ");

            while (true) {
                    String input = scanner.nextLine();
                    if("q".equals(input.trim())) {
                            break;
                    }
            }
            System.exit(0);
    }
}

Run & Verify Application

write some files in PROJECT_ROOT/the_source_dir/
run application then quit
see the files copied over PROJECT_ROOT/to the_dest_dir/

Open terminal at project root and execute the following:

mvn spring-boot:run