把某一目录下的.jpg文件和.png文件加上水印

package Demo;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
public class Demo4 {
    public static void main(String[] args) {
        del(new File("D:\\settingdownloads"));
    }

    public static void del(File f) {
        if (f.isDirectory()) {
            File[] files = f.listFiles();
            for (File file : files) {
                if (file.isDirectory()) del(file);
                if (file.isFile() &&file.getName().endsWith(".jpg") || file.getName().endsWith(".png")) {
                    Water(file);
                }
            }

        }
        if (f.isFile() && f.getName().endsWith(".jpg") || f.getName().endsWith(".png")) {
            Water(f);
        }
    }

    public static void Water(File file) {
        String f = file.getName();
        String t = f.substring(f.lastIndexOf(".")+1).toLowerCase();
        try {
            BufferedImage img = ImageIO.read((file));
            int width = img.getWidth();
            int height = img.getHeight();
            Graphics2D g = img.createGraphics();
            g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_GASP);
            g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            g.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_DEFAULT);
            String txt = "sanm";
            int size = 35;
            Font ff = Font.createFont(Font.TRUETYPE_FONT, new File("D:\\ITBYjava\\javase\\javase\\font\\FZCCHJW.TTF"));
            Font font = ff.deriveFont(Font.BOLD, size);
            g.setFont(font);
            FontMetrics fm = g.getFontMetrics();
            int fw = fm.stringWidth(txt);
            int fh = fm.getAscent() - (fm.getHeight() - fm.getAscent());
            g.setColor(new Color(255, 255, 255,80   ));
            int x = (width - fw) / 2;
            int y = (height - fh) / 3 + fh;
            g.drawString(txt, x, y);
            g.dispose();
            g.drawString(txt, x, y);
            ImageIO.write(img, t, file);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}