Archives: IO

Java – Convert InputStream to String

[code lang=”java”]import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

public class InputStreamToStringExample {

public static void main(String[] args) throws IOException {
//intilize an InputStream
InputStream is = new ByteArrayInputStream("file content".getBytes());

//read it with BufferedReader
BufferedReader br = new BufferedReader(new InputStreamReader(is));

StringBuilder sb = new StringBuilder();

String line;
while ((line = br.readLine()) != null) {
sb.append(line);
}

System.out.println(sb.toString());

br.close();
}

}[/code]


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

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

import java.io.File;

public class Main {

public static void main(String[] args) {
try {
File file = new File("pic.jpg");
long lastModified1 = file.lastModified();
FileUtils.touch(file);
long lastModified2 = file.lastModified();
System.out.println("File date / time was updated: " + (lastModified2 > lastModified1));
} catch (IOException ex) {
ex.printStackTrace();
}
}

}[/code]

Output:

File date / time was updated: true