Archives: File IO

Java – Convert PNG to JPEG Image File

[code lang=”java”]import java.awt.Color;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;

public class ConvertImageFile {

public static void main(String[] args) {

BufferedImage bufferedImage;

try {

//read image file
bufferedImage = ImageIO.read(new File("c:\\javanullpointer.png"));

// create a blank, RGB, same width and height, and a white background
BufferedImage newBufferedImage = new BufferedImage(bufferedImage.getWidth(),
bufferedImage.getHeight(), BufferedImage.TYPE_INT_RGB);
newBufferedImage.createGraphics().drawImage(bufferedImage, 0, 0, Color.WHITE, null);

// write to jpeg file
ImageIO.write(newBufferedImage, "jpg", new File("c:\\javanullpointer.jpg"));

System.out.println("Done");

} catch (IOException e) {

e.printStackTrace();

}

}

}[/code]


Java – Change File Date / Time using Commons FileUtils

Output:

File date / time was updated: true

Java – Calculate Directory Size using Commons FileUtils

[code lang=”java”]import java.io.File;
import org.apache.commons.io.FileUtils;

public class DirectorySizeSample {

public static void main(String[] args) {

// Using FileUtils.sizeOfDirectory() we can calculate
// the size of a directory including it sub directory
long size = FileUtils.sizeOfDirectory(new File("C:/Windows"));

System.out.println("Size: " + size + " bytes");

}
}[/code]