java7 NIO2 watching service API

• Z时代
• 2024-01-10
• 分类：综合

java7 NIO2新增了文件系统的相关事件处理API，为目录，文件新增修改删除等事件添加事件处理。

package reyo.sdk.utils.file;
import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardWatchEventKinds;
import java.nio.file.WatchEvent;
import java.nio.file.WatchEvent.Kind;
import java.nio.file.WatchKey;
import java.nio.file.WatchService;
public class NIO2WatchService {
    // WatchService 是线程安全的，跟踪文件事件的服务，一般是用独立线程启动跟踪
    public void watchRNDir(Path path) throws IOException, InterruptedException {
        try (WatchService watchService = FileSystems.getDefault().newWatchService()) {
            // 给path路径加上文件观察服务
            path.register(watchService, StandardWatchEventKinds.ENTRY_CREATE, StandardWatchEventKinds.ENTRY_MODIFY, StandardWatchEventKinds.ENTRY_DELETE);
            // start an infinite loop
            while (true) {
                // retrieve and remove the next watch key
                final WatchKey key = watchService.take();
                // get list of pending events for the watch key
                for (WatchEvent<?> watchEvent : key.pollEvents()) {
                    // get the kind of event (create, modify, delete)
                    final Kind<?> kind = watchEvent.kind();
                    // handle OVERFLOW event
                    if (kind == StandardWatchEventKinds.OVERFLOW) {
                        continue;
                    }
                    // 创建事件
                    if (kind == StandardWatchEventKinds.ENTRY_CREATE) {
                    }
                    // 修改事件
                    if (kind == StandardWatchEventKinds.ENTRY_MODIFY) {
                    }
                    // 删除事件
                    if (kind == StandardWatchEventKinds.ENTRY_DELETE) {
                    }
                    // get the filename for the event
                    @SuppressWarnings("unchecked")
                    final WatchEvent<Path> watchEventPath = (WatchEvent<Path>) watchEvent;
                    final Path filename = watchEventPath.context();
                    // print it out
                    System.out.println(kind + " -> " + filename);
                }
                // reset the keyf
                boolean valid = key.reset();
                // exit loop if the key is not valid (if the directory was
                // deleted, for
                if (!valid) {
                    break;
                }
            }
        }
    }
    /**
     * @param args
     */
    public static void main(String[] args) {
        // String sourceDir = "D:\\temp";
        //
        // Vector<String> v1 = FileOptionUtil.listAllDirAndFile(sourceDir,
        // sourceDir, true);
        //
        // for (int i = 0; i < v1.size(); i++) {
        // String fileNameb = v1.get(i);
        // if (fileNameb.indexOf(".") != -1) {
        // fileNameb = FileOptionUtil.getFileNameNoEx(fileNameb).substring(0,
        // FileOptionUtil.getFileNameNoEx(fileNameb).length() - 14) + "." +
        // FileOptionUtil.getExtensionName(fileNameb);
        // } else {
        // fileNameb = fileNameb.substring(0, fileNameb.length() - 14);
        // }
        //
        // }
        final Path path = Paths.get("D:\\temp");
        NIO2WatchService watch = new NIO2WatchService();
        try {
            watch.watchRNDir(path);
        } catch (IOException | InterruptedException ex) {
            System.err.println(ex);
        }
    }
}

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