java上传图片放大（小图等比放大，大图等比裁剪）

java上传图片放大（小图等比放大，大图等比裁剪）：

import java.awt.Graphics;    import java.awt.Image;    import java.awt.image.BufferedImage;    import java.io.File;    import java.io.FileOutputStream;    import java.io.IOException;    import javax.imageio.ImageIO;        import com.sun.image.codec.jpeg.JPEGCodec;    import com.sun.image.codec.jpeg.JPEGImageEncoder;        /**    * 上传图片-小图片放大图片不变型，但会模糊(取决于图片本身的像素)    *     * @author sunlight    *     */    public class AmplificationImage {            /**        * 判断图片是否大于目标尺寸        *         * @param srcPath        * @param maxWidth        * @param maxHeight        * @return        */        public static boolean isBigImage(String srcPath, int maxWidth, int maxHeight) {            BufferedImage bufferedImage = null;            try {                File of = new File(srcPath);                if (of.canRead()) {                    bufferedImage = ImageIO.read(of);                }            } catch (Exception e) {                return false;            }            if (bufferedImage != null) {                int width = bufferedImage.getWidth();                int height = bufferedImage.getHeight();                if (width > maxWidth && height > maxHeight) {                    return true;                }            }            return false;        }            /**        * 图片放大的方法（不会变色）        * @param inputUrl 图片输入路劲        * @param outputUrl 图片输出路劲        * @param maxWidth 目标宽        * @param maxHeight 目标高        * @param proportion 是否等比缩放        * @return        */        public static boolean zoomPicture(String inputUrl, String outputUrl,                int maxWidth, int maxHeight, boolean proportion) {            try {                // 获得源文件                File file = new File(inputUrl);                if (!file.exists()) {                    return false;                }                Image img = ImageIO.read(file);                // 判断图片格式是否正确                if (img.getWidth(null) == -1) {                    return false;                } else {                    int newWidth;                    int newHeight;                    // 判断是否是等比缩放                    if (proportion == true) {                        // 为等比缩放计算输出的图片宽度及高度                        double rate1 = ((double) img.getWidth(null))                                / (double) maxWidth;                        double rate2 = ((double) img.getHeight(null))                                / (double) maxHeight;                        // 根据缩放比率大的进行缩放控制                        double rate = rate1 > rate2 ? rate2 : rate1;                        newWidth = (int) (((double) img.getWidth(null)) / rate);                        newHeight = (int) (((double) img.getHeight(null)) / rate);                    } else {                        newWidth = maxWidth; // 输出的图片宽度                        newHeight = maxHeight; // 输出的图片高度                    }                    BufferedImage tag = new BufferedImage((int) newWidth,                            (int) newHeight, BufferedImage.TYPE_INT_RGB);                        tag.getGraphics().drawImage(                            img.getScaledInstance(newWidth, newHeight,                                    Image.SCALE_SMOOTH), 0, 0, null);                    FileOutputStream out = new FileOutputStream(outputUrl);                    // JPEGImageEncoder可适用于其他图片类型的转换                    JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);                    encoder.encode(tag);                    out.close();                }            } catch (Exception e) {                e.printStackTrace();            }            return true;        }                /**        * 对图片进行放大（部分图片会变红）        * @param srcPath        *            原始图片路径(绝对路径)        * @param newPath        *            放大后图片路径（绝对路径）        * @param times        *            放大倍数        * @return 是否放大成功        */            public static boolean zoomInImage(String srcPath, String newPath,                int maxWidth, int maxHeight) {            BufferedImage bufferedImage = null;            try {                File of = new File(srcPath);                if (of.canRead()) {                    bufferedImage = ImageIO.read(of);                }            } catch (IOException e) {                // TODO: 打印日志                return false;            }            if (bufferedImage != null) {                bufferedImage = zoomInImage(bufferedImage, maxWidth, maxHeight);                try {                    // TODO: 这个保存路径需要配置下子好一点                    ImageIO.write(bufferedImage, "JPG", new File(newPath)); // 保存修改后的图像,全部保存为JPG格式                } catch (IOException e) {                    // TODO 打印错误信息                    return false;                }            }            return true;        }            /**        * 对图片进行放大        *         * @param originalImage        *            原始图片        * @param maxWidth        *            目标宽度        * @param maxHeight        *            目标高度        * @return        */        private static BufferedImage zoomInImage(BufferedImage originalImage,                int maxWidth, int maxHeight) {            int times = 1; // 放大倍数            int width = originalImage.getWidth();            int height = originalImage.getHeight();            double sw = (maxWidth * 1.0) / (width * 1.0);            double sh = (maxHeight * 1.0) / (height * 1.0);            if (width > maxWidth && height > maxHeight) {                return originalImage;            } else if (width < maxWidth && height < maxHeight) {                if (sw > sh) {                    times = (int) (sw + 0.8);                } else {                    times = (int) (sh + 0.8);                }            } else if (width < maxWidth && height > maxHeight) {                times = (int) (sw + 0.8);            } else {                times = (int) (sh + 0.8);            }            int lastW = times * width;            int lastH = times * height;            BufferedImage newImage = new BufferedImage(lastW, lastH, originalImage                    .getType());            Graphics g = newImage.getGraphics();            g.drawImage(originalImage, 0, 0, lastW, lastH, null);            g.dispose();            return newImage;        }    }