yangys
2025-09-29 4c7296d45efe849dc70a3b2e2240c905481a91c9
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package org.springblade.mdm.machinefile.filewatch;
 
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
 
import java.io.IOException;
import java.nio.file.*;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
 
import static java.nio.file.StandardWatchEventKinds.*;
import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
@Slf4j
@Service
public class FileWatcherService {
 
    private final ExecutorService executor = Executors.newCachedThreadPool();
    private final Map<Path, WatchService> watchServices = new HashMap<>();
    private final Map<Path, FileChangeListener> listeners = new HashMap<>();
 
    Cache<Path, FileState> fileStates = CacheBuilder.newBuilder()
        .maximumSize(10) // 最大容量3
        .build();
    enum FileState {
        CREATED, MODIFIED, STABLE
    }
 
    public interface FileChangeListener {
        void onFileCreated(Path filePath);
        void onFileModified(Path filePath);
        void onFileDeleted(Path filePath);
    }
 
    public void watchDirectory(Path directory, FileChangeListener listener) throws IOException {
        if (!Files.isDirectory(directory)) {
            throw new IllegalArgumentException("Path must be a directory: " + directory);
        }
 
        if (watchServices.containsKey(directory)) {
            throw new IllegalStateException("Directory is already being watched: " + directory);
        }
 
        WatchService watchService = FileSystems.getDefault().newWatchService();
        directory.register(watchService, ENTRY_CREATE, ENTRY_MODIFY, ENTRY_DELETE);
 
        watchServices.put(directory, watchService);
        listeners.put(directory, listener);
 
        executor.submit(() -> {
            try {
                while (true) {
                    WatchKey key = watchService.take();
 
                    for (WatchEvent<?> event : key.pollEvents()) {
                        WatchEvent.Kind<?> kind = event.kind();
 
                        @SuppressWarnings("unchecked")
                        WatchEvent<Path> ev = (WatchEvent<Path>) event;
                        Path fileName = ev.context();
                        Path fullPath = directory.resolve(fileName);
 
                        FileState currentState = fileStates.getIfPresent(fullPath);
                        currentState = (currentState == null) ? FileState.STABLE : currentState;
 
                        FileChangeListener currentListener = listeners.get(directory);
                        if (currentListener == null) break;
 
                        if (kind == ENTRY_CREATE) {
                            if (currentState != FileState.CREATED) {
                                log.info("新文件创建: {}", fullPath);
                                fileStates.put(fullPath, FileState.CREATED);
                            }
                            currentListener.onFileCreated(fullPath);
                        } else if (kind == ENTRY_MODIFY) {
                            if (currentState == FileState.CREATED) {
                                // 忽略创建后的第一次修改
                                log.info("文件创建时的修改事件,忽略: {}", fullPath);
                                fileStates.put(fullPath, FileState.STABLE);
                            } else {
                                currentListener.onFileModified(fullPath);
                            }
                        } else if (kind == ENTRY_DELETE) {
                            currentListener.onFileDeleted(fullPath);
                        }
                    }
                    boolean valid = key.reset();
                    if (!valid) {
                        break;
                    }
                }
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            } catch (ClosedWatchServiceException e) {
                // Service was closed, exit normally
            }
        });
    }
 
    public void stopWatching(Path directory) throws IOException {
        WatchService watchService = watchServices.remove(directory);
        listeners.remove(directory);
        if (watchService != null) {
            watchService.close();
        }
    }
 
    public void shutdown() {
        executor.shutdownNow();
        watchServices.values().forEach(watchService -> {
            try {
                watchService.close();
            } catch (IOException e) {
                // Ignore on shutdown
            }
        });
        watchServices.clear();
        listeners.clear();
    }
 
    public Map<Path, WatchService> getWatchedDirectories(){
        return this.watchServices;
    }
}