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;
    }

}