java - 调整图像文件的大小

Question

在 Java 中，我将图像文件从一个位置复制到另一个位置。程序正在正确执行，但我希望目标文件大小与源文件大小不同。还有其他方法可以在新位置调整文件大小吗？我正在使用以下代码:

public class NewJFrame extends javax.swing.JFrame {

    public NewJFrame() {
        initComponents();
    }

    public static void copyFile(File sourceFile, File destFile)
            throws IOException {
        if (!destFile.exists()) {
            destFile.createNewFile();
        }

        FileChannel source = null;
        FileChannel destination = null;
        try {
            source = new FileInputStream(sourceFile).getChannel();
            destination = new FileOutputStream(destFile).getChannel();

            // previous code: destination.transferFrom(source, 0, source.size());
            // to avoid infinite loops, should be:
            long count = 0;
            long size = source.size();
            while ((count += destination.transferFrom(source, count, size
                    - count)) < size)
                ;
        } finally {
            if (source != null) {
                source.close();
            }
            if (destination != null) {
                destination.close();
            }
        }
    }

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
        try {
            File sourceFile = new File(
                    "d:/adesh/golden_temple_amritsar_india-normal.jpg");

            File destFile = new File(
                    "d:/adesh2/golden_temple_amritsar_india-normal.jpg");

            copyFile(sourceFile, destFile);
        } catch (Exception ex) {
        }

    }

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {

        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new NewJFrame().setVisible(true);
            }
        });
    }

    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
}

Answer 1

这是根据您的规范调整图像大小的代码。在 copyFile 方法内部，

int width=100,height=75; /* set the width and height here */

BufferedImage inputImage=ImageIO.read(sourceFile);

BufferedImage outputImage=new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

Graphics2D g=outputImage.createGraphics();

g.setRenderingHint(RenderingHints.KEY_INTERPOLATION,RenderingHints.VALUE_INTERPOLATION_BICUBIC);

g.clearRect(0, 0, width, height);

g.drawImage(inputImage, 0, 0, width, height, null);

g.dispose();

ImageIO.write(outputImage,"jpg",destFile); /* first parameter is the object of the BufferedImage, second parameter is the type of image that you are going to write, you can use jpg, bmp, png etc and the third parameter is the destination file object. */