java - How to monitor folder/directory in spring?

Question

I wan't to write Spring Boot Application in spring which will be monitoring directory in windows, and when I change sub folder or add new one or delete existing one I wanna get information about that.

How can i do that? I have read this one: http://docs.spring.io/spring-integration/reference/html/files.html and each result under 'spring file watcher' in google, but I can't find solution...

Do you have a good article or example with something like this? I wan't it to like like this:

@SpringBootApplication
@EnableIntegration
public class SpringApp{

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

    @Bean
    public WatchService watcherService() {
        ...//define WatchService here
    }
}

Regards

Answer 1

spring-boot-devtools has FileSystemWatcher

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
</dependency>

FileWatcherConfig

@Configuration
public class FileWatcherConfig {
    @Bean
    public FileSystemWatcher fileSystemWatcher() {
        FileSystemWatcher fileSystemWatcher = new FileSystemWatcher(true, Duration.ofMillis(5000L), Duration.ofMillis(3000L));
        fileSystemWatcher.addSourceFolder(new File("/path/to/folder"));
        fileSystemWatcher.addListener(new MyFileChangeListener());
        fileSystemWatcher.start();
        System.out.println("started fileSystemWatcher");
        return fileSystemWatcher;
    }

    @PreDestroy
    public void onDestroy() throws Exception {
        fileSystemWatcher().stop();
    }
}

MyFileChangeListener

@Component
public class MyFileChangeListener implements FileChangeListener {

    @Override
    public void onChange(Set<ChangedFiles> changeSet) {
        for(ChangedFiles cfiles : changeSet) {
            for(ChangedFile cfile: cfiles.getFiles()) {
                if( /* (cfile.getType().equals(Type.MODIFY) 
                     || cfile.getType().equals(Type.ADD)  
                     || cfile.getType().equals(Type.DELETE) ) && */ !isLocked(cfile.getFile().toPath())) {
                    System.out.println("Operation: " + cfile.getType() 
                      + " On file: "+ cfile.getFile().getName() + " is done");
                }
            }
        }
    }
    
    private boolean isLocked(Path path) {
        try (FileChannel ch = FileChannel.open(path, StandardOpenOption.WRITE); FileLock lock = ch.tryLock()) {
            return lock == null;
        } catch (IOException e) {
            return true;
        }
    }

}