JAVA轻量级文件监控

原文地址：http://blog.csdn.net/three_man/article/details/31012903?utm_source=tuicool

介绍

本文主要介绍一种轻量级的文件监控方式，对文件的Create & Change & Delete，都有一个对应的Event方法来进行处理。对于核心的File Monitor Class，我们继承一个监听适配器类FileAlterationListenerAdaptor，这样会更方便，就不用再去重写每个Event方法。

 package shuai.study.file.generator;

 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Paths;
 import java.util.Date;

 import org.apache.log4j.Logger;

 import shuai.study.file.tooler.CommonTooler;

 /**
  * @author shengshu
  *
  */
 public class FileGenerator implements Runnable {
     private static final Logger LOG = Logger.getLogger(FileGenerator.class);

     private String directory = null;

     private static Date date = new Date();

     public FileGenerator(String directory) {
         this.directory = directory;
     }

     private void generator(String directory) {
         for (int i = 0; i < 10; i++) {
             String fileName = CommonTooler.getDateTimeFormat(date) + "-" + Thread.currentThread().getId() + i + ".pm";

             LOG.info("[Path]: " + directory + "/" + fileName);

             try {
                 // Create file (path: directory/fileName)
                 Files.createFile(Paths.get(directory, fileName));
             } catch (IOException ioe) {
                 ioe.printStackTrace();
             }
         }
     }

     @Override
     public void run() {
         this.generator(directory);
     }
 }

 package shuai.study.file.monitor;

 import java.io.File;
 import java.io.IOException;

 import org.apache.commons.io.FileUtils;
 import org.apache.commons.io.FilenameUtils;
 import org.apache.commons.io.filefilter.FileFilterUtils;
 import org.apache.commons.io.monitor.FileAlterationListenerAdaptor;
 import org.apache.commons.io.monitor.FileAlterationMonitor;
 import org.apache.commons.io.monitor.FileAlterationObserver;
 import org.apache.log4j.Logger;

 import shuai.study.file.tooler.CommonTooler;

 /**
  * @author shengshu
  *
  */
 public class FileMonitor extends FileAlterationListenerAdaptor {
     private static final Logger LOG = Logger.getLogger(FileMonitor.class);

     private static FileMonitor fileMonitor;

     private static int pageNumber = 0;

     private FileMonitor() {

     }

     // Get singleton object instance
     public static FileMonitor getFileMonitor() {
         if (fileMonitor == null) {
             synchronized (FileMonitor.class) {
                 if (fileMonitor == null) {
                     fileMonitor = new FileMonitor();
                 }
             }
         }

         return fileMonitor;
     }

     // Create file event
     @Override
     public void onFileCreate(File file) {
         LOG.info("[Create]: " + file.getAbsolutePath());

         String fileAbsolutePath = file.getAbsolutePath();
         String fileAbsoluteParentPath = file.getParent();
         String fileBaseName = FilenameUtils.getBaseName(fileAbsolutePath);

         File destFile = new File(fileAbsoluteParentPath + File.separator + fileBaseName + "-" + CommonTooler.pagingFormat(pageNumber) + ".xml");

         try {
             FileUtils.moveFile(file, destFile);
         } catch (IOException ioe) {
             ioe.printStackTrace();
         }

         pageNumber++;
     }

     // Change file event
     @Override
     public void onFileChange(File file) {
         LOG.info("[Change]: " + file.getAbsolutePath());
     }

     // Delete file event
     @Override
     public void onFileDelete(File file) {
         LOG.info("[Delete]: " + file.getAbsolutePath());
     }

     public void monitor(String directory, int interval) {
         // Observer file whose suffix is pm
         FileAlterationObserver fileAlterationObserver = new FileAlterationObserver(directory, FileFilterUtils.and(FileFilterUtils.fileFileFilter(),
                 FileFilterUtils.suffixFileFilter(".pm")), null);

         // Add listener for event (file create & change & delete)
         fileAlterationObserver.addListener(this);

         // Monitor per interval
         FileAlterationMonitor fileAlterationMonitor = new FileAlterationMonitor(interval, fileAlterationObserver);

         try {
             // Start to monitor
             fileAlterationMonitor.start();
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
 }

 package shuai.study.file.tester;

 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Paths;

 import org.apache.log4j.Logger;

 import shuai.study.file.generator.FileGenerator;
 import shuai.study.file.monitor.FileMonitor;

 /**
  * @author shengshu
  *
  */
 public class FileTester {
     private static final Logger LOG = Logger.getLogger(FileTester.class);

     private static String directory = "/home/omc/tmp";

     public static void main(String[] args) {
         // Create directory if it does not exist
         try {
             Files.createDirectory(Paths.get(directory));
         } catch (IOException ioe) {
             ioe.printStackTrace();
         }

         LOG.info("File Monitor...");
         // Start to monitor file event per 500 milliseconds
         FileMonitor.getFileMonitor().monitor(directory, 500);

         LOG.info("File Generater...");
         // New runnable instance
         FileGenerator fileGeneratorRunnable = new FileGenerator(directory);

         // Start to multi-thread for generating file
         for (int i = 0; i < 10; i++) {
             Thread fileGeneratorThread = new Thread(fileGeneratorRunnable);
             fileGeneratorThread.start();
         }
     }

 }

 package shuai.study.file.tooler;

 import java.text.SimpleDateFormat;
 import java.util.Date;

 /**
  * @author shengshu
  *
  */
 public class CommonTooler {

     // Date time format
     public static String getDateTimeFormat(Date date) {
         SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyyMMdd-HHmm");
         String dateTime = simpleDateFormat.format(date);

         return dateTime;
     }

     // Page format
     public static String pagingFormat(int pageNumber) {
         String pageNumberStr = "P00";

         if (pageNumber < 0) {
             throw new NumberFormatException("The page number should not be negative");
         }

         if (pageNumber < 10) {
             pageNumberStr = String.format("P0%d", pageNumber);
         } else {
             pageNumberStr = String.format("P%d", pageNumber);
         }

         return pageNumberStr;
     }

 }