【Java】图片高质量缩放类

package com.test;  

import com.sun.image.codec.jpeg.JPEGImageEncoder;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGEncodeParam;
import javax.swing.*;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.awt.image.Kernel;
import java.awt.image.ConvolveOp;  

public class ImageUtil {  

    public static void resize(File originalFile, File resizedFile,
            int newWidth, float quality) throws IOException {  

        if (quality > 1) {
            throw new IllegalArgumentException(
                    "Quality has to be between 0 and 1");
        }  

        ImageIcon ii = new ImageIcon(originalFile.getCanonicalPath());
        Image i = ii.getImage();
        Image resizedImage = null;  

        int iWidth = i.getWidth(null);
        int iHeight = i.getHeight(null);  

        if (iWidth > iHeight) {
            resizedImage = i.getScaledInstance(newWidth, (newWidth * iHeight)
                    / iWidth, Image.SCALE_SMOOTH);
        } else {
            resizedImage = i.getScaledInstance((newWidth * iWidth) / iHeight,
                    newWidth, Image.SCALE_SMOOTH);
        }  

        // This code ensures that all the pixels in the image are loaded.
        Image temp = new ImageIcon(resizedImage).getImage();  

        // Create the buffered image.
        BufferedImage bufferedImage = new BufferedImage(temp.getWidth(null),
                temp.getHeight(null), BufferedImage.TYPE_INT_RGB);  

        // Copy image to buffered image.
        Graphics g = bufferedImage.createGraphics();  

        // Clear background and paint the image.
        g.setColor(Color.white);
        g.fillRect(0, 0, temp.getWidth(null), temp.getHeight(null));
        g.drawImage(temp, 0, 0, null);
        g.dispose();  

        // Soften.
        float softenFactor = 0.05f;
        float[] softenArray = { 0, softenFactor, 0, softenFactor,
                1 - (softenFactor * 4), softenFactor, 0, softenFactor, 0 };
        Kernel kernel = new Kernel(3, 3, softenArray);
        ConvolveOp cOp = new ConvolveOp(kernel, ConvolveOp.EDGE_NO_OP, null);
        bufferedImage = cOp.filter(bufferedImage, null);  

        // Write the jpeg to a file.
        FileOutputStream out = new FileOutputStream(resizedFile);  

        // Encodes image as a JPEG data stream
        JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);  

        JPEGEncodeParam param = encoder
                .getDefaultJPEGEncodeParam(bufferedImage);  

        param.setQuality(quality, true);  

        encoder.setJPEGEncodeParam(param);
        encoder.encode(bufferedImage);
    } // Example usage  

    public static void main(String[] args) throws IOException {
//       File originalImage = new File("C:\\11.jpg");
//       resize(originalImage, new File("c:\\11-0.jpg"),150, 0.7f);
//       resize(originalImage, new File("c:\\11-1.jpg"),150, 1f);
         File originalImage = new File("C:\\1207.gif");
         resize(originalImage, new File("c:\\1207-0.jpg"),150, 0.7f);
         resize(originalImage, new File("c:\\1207-1.jpg"),150, 1f);
    }
}