文件夹监视器Java代码两次打印报告

Question

Using some answers from this site I created a small Folder Monitor app in Java. It is supposed to check for changes to a specific folder and output those changes to a text file. Unfortunately it prints the report twice for every change. The problem is I cannot figure out where the first line of the report comes from. Please help me understand what am I doing wrong.

Please find the code below. I removed part of the code as it does not affect the Q&A.

import java.io.File;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.text.SimpleDateFormat;
import java.util.Date;
import org.apache.commons.io.monitor.FileAlterationListener;
import org.apache.commons.io.monitor.FileAlterationListenerAdaptor;
import org.apache.commons.io.monitor.FileAlterationMonitor;
import org.apache.commons.io.monitor.FileAlterationObserver;

public class FolderMonitor {

    public FolderMonitor() {}

    //path to a folder you are monitoring
    public static final String FOLDER = "D:\\WatchedDir";

    public static void main(String[] args) throws Exception 
    {
        System.out.println("monitoring started");
        // The monitor will perform polling on the folder every 5 seconds
        final long pollingInterval = 6 * 1000;

        // Let's get a directory as a File object and sort all its files.
        File folderToMonitor = new File(FOLDER);
        File outputFile = new File("H:\\Dir_changes.txt");          

        if (!folderToMonitor.exists()) 
        {
            // Test to see if monitored folder exists
            throw new RuntimeException("Directory not found: " + FOLDER);
        }           

        FileAlterationObserver observer = new FileAlterationObserver(folderToMonitor);
        FileAlterationMonitor monitor = new FileAlterationMonitor(pollingInterval);
        FileAlterationListener listener = new FileAlterationListenerAdaptor() 
        {           
            // Is triggered when a file in the monitored folder is modified from 
            @Override
            public void onFileChange(File file) 
            {
                // "file" is the reference to the newly created file                
                try {writeToFile(outputFile, convertLongToDate(outputFile.lastModified()), ("File modified: "+ file.getCanonicalPath()));}               
                    catch (IOException e) {e.printStackTrace();} 
            }           
        };

        observer.addListener(listener);
        monitor.addObserver(observer);
        monitor.start();
    }

    private static void writeToFile(File filePath, String timeStamp, String caughtChange) throws IOException
    {
        FileWriter fileWriter = new FileWriter(filePath,true);

        BufferedWriter bufferFileWriter  = new BufferedWriter(fileWriter);

        fileWriter.append("\r" + timeStamp + " - " + caughtChange + "\r");

        bufferFileWriter.close();     
    }

    private static String convertLongToDate(long input)
    {
        Date date = new Date(input);
        Calendar cal = new GregorianCalendar();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MMM/dd hh:mm:ss z");
        sdf.setCalendar(cal);
        cal.setTime(date);
        return sdf.format(date);
    }
}

The output looks like this:

1454622374878 File modified: D:\\WatchedDir\\second\\inside3.txt 2016/Feb/04 04:46:25 EST - File modified: D:\\WatchedDir\\second\\inside3.txt

I can not figure out where the highlighted (bold) part comes from and how to get rid of it. Please help!

Answer 1

I ran the same code that you posted and don't see the extra output in the .txt file. can you please try it by directing the output to a new file and see if it makes any difference

Answer 2

For some reason Eclipse was executing code that I have already removed from the class and saved the changes.

After I have restarted Eclipse and executed the code again, everything was running fine (surprise).

I considered deleting this post but I decided to leave it just in case someone will be looking for such a piece of code. I will leave it to the moderators to decide if this question should be deleted.