春天如何监视文件夹/目录？

Question

我不会在Spring中编写Spring Boot Application，它将监视Windows中的目录，当我更改子文件夹或添加新的文件夹或删除现有的文件夹时，我想获取有关该文件夹的信息。

我怎样才能做到这一点？我已经读过这篇文章：http : //docs.spring.io/spring-integration/reference/html/files.html 和google中“ spring file watcher”下的每个结果，但是我找不到解决方案...

您是否有类似这样的好文章或示例？我不想这样：

@SpringBootApplication
@EnableIntegration
public class SpringApp{

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

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

问候

Answer 1

spring-boot-devtools 已 FileSystemWatcher

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

文件观察者配置

@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();
    }
}

我的文件更改监听器

@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;
        }
    }

}

Answer 2

从 Java 7 开始，有WatchService - 这将是最好的解决方案。

Spring 配置可能如下所示：

@Slf4j
@Configuration
public class MonitoringConfig {

    @Value("${monitoring-folder}")
    private String folderPath;

    @Bean
    public WatchService watchService() {
        log.debug("MONITORING_FOLDER: {}", folderPath);
        WatchService watchService = null;
        try {
            watchService = FileSystems.getDefault().newWatchService();
            Path path = Paths.get(folderPath);

            if (!Files.isDirectory(path)) {
                throw new RuntimeException("incorrect monitoring folder: " + path);
            }

            path.register(
                    watchService,
                    StandardWatchEventKinds.ENTRY_DELETE,
                    StandardWatchEventKinds.ENTRY_MODIFY,
                    StandardWatchEventKinds.ENTRY_CREATE
            );
        } catch (IOException e) {
            log.error("exception for watch service creation:", e);
        }
        return watchService;
    }
}

和用于启动监控本身的 Bean：

@Slf4j
@Service
@AllArgsConstructor
public class MonitoringServiceImpl {

    private final WatchService watchService;

    @Async
    @PostConstruct
    public void launchMonitoring() {
        log.info("START_MONITORING");
        try {
            WatchKey key;
            while ((key = watchService.take()) != null) {
                for (WatchEvent<?> event : key.pollEvents()) {
                    log.debug("Event kind: {}; File affected: {}", event.kind(), event.context());
                }
                key.reset();
            }
        } catch (InterruptedException e) {
            log.warn("interrupted exception for monitoring service");
        }
    }

    @PreDestroy
    public void stopMonitoring() {
        log.info("STOP_MONITORING");

        if (watchService != null) {
            try {
                watchService.close();
            } catch (IOException e) {
                log.error("exception while closing the monitoring service");
            }
        }
    }
}

此外，您必须@EnableAsync为您的应用程序类（它的配置）进行设置。

并从application.yml：

监控文件夹：C:\Users\nazar_art

使用 Spring Boot 进行测试2.3.1。

还用于异步池的配置：

@Slf4j
@EnableAsync
@Configuration
@AllArgsConstructor
@EnableConfigurationProperties(AsyncProperties.class)
public class AsyncConfiguration implements AsyncConfigurer {

    private final AsyncProperties properties;

    @Override
    @Bean(name = "taskExecutor")
    public Executor getAsyncExecutor() {
        log.debug("Creating Async Task Executor");
        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
        taskExecutor.setCorePoolSize(properties.getCorePoolSize());
        taskExecutor.setMaxPoolSize(properties.getMaxPoolSize());
        taskExecutor.setQueueCapacity(properties.getQueueCapacity());
        taskExecutor.setThreadNamePrefix(properties.getThreadName());
        taskExecutor.initialize();
        return taskExecutor;
    }

    @Bean
    public TaskScheduler taskScheduler() {
        return new ConcurrentTaskScheduler();
    }

    @Override
    public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
        return new CustomAsyncExceptionHandler();
    }
}

自定义异步异常处理程序在哪里：

@Slf4j
public class CustomAsyncExceptionHandler implements AsyncUncaughtExceptionHandler {

    @Override
    public void handleUncaughtException(Throwable throwable, Method method, Object... objects) {
        log.error("Exception for Async execution: ", throwable);
        log.error("Method name - {}", method.getName());
        for (Object param : objects) {
            log.error("Parameter value - {}", param);
        }
    }
}

属性文件中的配置：

async-monitoring:
  core-pool-size: 10
  max-pool-size: 20
  queue-capacity: 1024
  thread-name: 'async-ex-'

Answer 3

您可以为此使用纯 Java，无需 spring https://docs.oracle.com/javase/tutorial/essential/io/notification.html