jdk7 WatchService 监控文件夹_jdk7的watchservice监测文件夹-优快云博客

本文链接：https://blog.youkuaiyun.com/shjniu3000/article/details/52598413

本文介绍了一个使用Java NIO的WatchService接口实现的文件监听服务示例。该服务能够监听指定目录下的文件创建、删除及修改事件，并实时打印出发生的事件类型及文件名。

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package test;

import static java.nio.file.StandardWatchEventKinds.ENTRY_CREATE;
import static java.nio.file.StandardWatchEventKinds.ENTRY_DELETE;
import static java.nio.file.StandardWatchEventKinds.ENTRY_MODIFY;
import static java.nio.file.StandardWatchEventKinds.OVERFLOW;

import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.WatchEvent;
import java.nio.file.WatchKey;
import java.nio.file.WatchService;

public class TestWatcherService {
	
	private WatchService watcher;
	
	public TestWatcherService(Path path) throws IOException{
		watcher = FileSystems.getDefault().newWatchService();
		path.register(watcher, ENTRY_CREATE, ENTRY_DELETE, ENTRY_MODIFY);
	}
	
	public void handleEvents() throws InterruptedException{
		while(true){
			WatchKey key = watcher.take();
			
			for(WatchEvent<?> event : key.pollEvents()){
				WatchEvent.Kind kind = event.kind();
				
				if(kind == OVERFLOW){ //事件可能是lost or discarded
					continue;
				}
				
				WatchEvent<Path> e = (WatchEvent<Path>) event;
				Path fileName = e.context();
				
				System.out.println("happen: "+kind.name()+"----"+fileName);
				System.out.println("=======================");
			}
			
			if(!key.reset()){
				break;
			}
		}
	}
	
	public static void main(String[] args) throws InterruptedException, IOException {
		new TestWatcherService(Paths.get("E:\\test")).handleEvents();  
	}

	/*
	 情况1 文件操作：
	操作：新建一个文本文档，
	happen: ENTRY_CREATE----新建文本文档.txt
	=======================

	操作：改名为1
	happen: ENTRY_DELETE----新建文本文档.txt
	=======================
	happen: ENTRY_CREATE----1.txt
	=======================
	happen: ENTRY_MODIFY----1.txt
	=======================

	操作：修改内容
	happen: ENTRY_MODIFY----1.txt
	=======================

	操作：删除
	happen: ENTRY_DELETE----1.txt
	=======================

	情况2：文件夹操作
	操作：新建文件夹
	happen: ENTRY_CREATE----新建文件夹
	=======================

	操作：改名文件夹
	happen: ENTRY_DELETE----新建文件夹
	=======================
	happen: ENTRY_CREATE----2
	=======================

	操作：删除文件夹
	happen: ENTRY_DELETE----2
	=======================

	情况3：文件夹中文件的相关操作
	操作：文件夹中建立、删除、修改文件，只会报如下错误
	happen: ENTRY_MODIFY----1
	*/
}