File Modified Date Manipulation in Java

This example demonstrates the basic data manipulation operation in a File object. Java File object has set of methods to perform the following operations:

• Get the file last modified date
• Change the file modified date

Lets look at the example to see how the above operations are implemented in Java example program. We use SImpleDateFormat for passing the proper date and converting to the desired format.

FileModifiedDateExample.java

[code lang=”java”]package javabeat.net.core;

import java.io.File;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class FileModifiedDateExample{
public static void main(String[] args) throws ParseException{
File fileObj = new File("/var/www/license.txt");

System.out.println("Last Modified Date Without Format : " + fileObj.lastModified());
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("dd/MMM/yyyy HH:mm:ss");
System.out.println("Last Modified Date After Format : " + simpleDateFormat.format(fileObj.lastModified()));

String changeToThisDate = "26/Jan/2014 01:20:20";

//Converting to milliseconds
Date newModifiedDate = simpleDateFormat.parse(changeToThisDate);
fileObj.setLastModified(newModifiedDate.getTime());

System.out.println("Lastest Last Modified Date : "
+ simpleDateFormat.format(fileObj.lastModified()));
}
}
[/code]

Output…

[code]
Last Modified Date Without Format : 1390679420000
Last Modified Date After Format : 26/Jan/2014 01:20:20
Lastest Last Modified Date : 26/Jan/2014 01:20:20
[/code]

If you are not given the proper format, the you would encounter the following exception:

[code]
Exception in thread "main" java.text.ParseException: Unparseable date: "26/Jan/2014 "
at java.text.DateFormat.parse(DateFormat.java:354)
at javabeat.net.core.FileModifiedDateExample.main(FileModifiedDateExample.java:19)
[/code]