超级简单的文件监听器

<listenerUtil > 监听器工具类

package com.*.listener;

import org.apache.commons.lang.ObjectUtils;
import org.apache.commons.lang.StringUtils;

import java.io.File;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

/**
 * Created by 22431 on 2016/8/22.
 */
public class ListenerUtil implements Runnable {

    //是否启动监听
    private boolean startFlag = true;

   //5秒监听一次
    private int interval = 5000;

    private static File fileName ;
    private static Map<String , Long> objItem ;

    //初始化
    static {
        fileName = new File("D:/testListener.txt");
        objItem = new HashMap<String, Long>();
        addFileName(fileName);
    }
    /**
     * 添加监听文件
     */
    public static void addFileName(File fileName){
        //判断文件路径是否为空
        if (fileName.exists() && fileName.isFile()){
            try {
                long lastModifyTime = fileName.lastModified();
                objItem.put(fileName.getPath(), lastModifyTime);
                System.out.println("添加文件成功");
            }catch (Exception e){
                e.printStackTrace();
                System.out.println("文件添加失败");
            }
        }
    }

    /**
     * 监听文件是否有变动
     */
    public void checkMap(Map<String , Long> map) {
        if (map != null && !map.isEmpty()) {
            String filePath = "";
            Set<String> set = map.keySet();
            for (String string : set) {
                filePath = string;
            }
            File file = new File(filePath);
            long newModifyTime = file.lastModified();
            long lastModifyTime = map.get(filePath);
            if (newModifyTime != lastModifyTime){
                System.out.println("文件改动啦！");
                objItem.clear();
                objItem.put(file.getPath() , file.lastModified());
            }
        }
    }


    @Override
    public void run() {
        while (startFlag){
            try {
                Thread.sleep(interval);
                checkMap(objItem);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    //测试
    public static void main(String[] args) {
        (new Thread(new ListenerUtil())).start();
    }
}