java生成缩略图

/**  
 * 缩放gif图片  
 * @param originalFile 原图片  
 * @param resizedFile 缩放后的图片  
 * @param newWidth 宽度  
 * @param quality 缩放比例 (等比例)  
 * @throws IOException  
 */  
public  static void resize(File originalFile, File resizedFile, int newWidth, float quality) throws IOException {   
    if (quality < 0 || 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);   
}