import javax.imageio.ImageIO;import java.awt.*;import java.awt.image.BufferedImage;import java.io.File;import java.io.IOException;import java.text.DecimalFormat;public class ImageDiff {    //不同的像素标记为红色    public static final int RGB_RED = 16711680;    //允许的Red，Green，Blue单个维度的像素差值    public static final int DIFF_ALLOW_RANGE = 5;    //不同像素点统计值    public static int diffPointCount = 0;    //从rgb值中抽取red    public static int getRed(int rgbValue){        return rgbValue & 0xff0000 >> 16;    }    //从rgb值中抽取green    public static int getGreen(int rgbValue){        return rgbValue & 0xff00 >> 8;    }    //从rgb值中抽取blue    public static int getBlue(int rgbValue){        return rgbValue & 0xff;    }    /**     * 比较两图片，并用红色标出不同的像素点，然后保存差异图片到本地，打印匹配率     * @param srcImgPath     * @param targetImgPath     */    public static void compareImages(String srcImgPath,String targetImgPath){        try {            BufferedImage srcImg = ImageIO.read(new File(srcImgPath));            BufferedImage targetImg = ImageIO.read(new File(targetImgPath));            diffPointCount = 0;            BufferedImage diffImg = srcImg;            int srcHeight = srcImg.getHeight();            int srcWidth = srcImg.getWidth();            //修改待比较图片的尺寸以适应源图片的尺寸            targetImg = changeImageSize(targetImg,srcHeight,srcWidth);            int srcRgb;            int targetRgb;            for(int h = 0;h<srcHeight;h++){                for(int w=0;w<srcWidth;w++){                    srcRgb = srcImg.getRGB(w,h);                    targetRgb = targetImg.getRGB(w,h);                    if( Math.abs(getRed(srcRgb) - getRed(targetRgb))>DIFF_ALLOW_RANGE ||                            Math.abs(getGreen(srcRgb) - getGreen(targetRgb))>DIFF_ALLOW_RANGE||                            Math.abs(getBlue(srcRgb) - getBlue(targetRgb))>DIFF_ALLOW_RANGE){                        diffImg.setRGB(w,h, RGB_RED);                        diffPointCount++;                    }                }            }            //保存差异图片            ImageIO.write(diffImg,"jpg",new File("diffImg.jpg"));            System.out.println("保存差异图片成功！");            //计算相似度(保留小数点后四位）            int totalPixel = srcHeight*srcWidth;            DecimalFormat decimalFormat = new DecimalFormat("#.####");            double matchRate = (totalPixel-diffPointCount)/(totalPixel*1.0);            System.out.println("图片相似度为： "+decimalFormat.format(matchRate)+"%");        }catch (Exception ex){            ex.printStackTrace();        }    }    /**     * 修改BufferedImage中的图片尺寸，以便和源图片进行比较     * @param image     * @param newHeight     * @param newWidth     * @return     */    public static BufferedImage changeImageSize(BufferedImage image,int newHeight,int newWidth){        Image img = image.getScaledInstance(newWidth,newHeight,Image.SCALE_SMOOTH);        int width = img.getWidth(null);        int height = img.getHeight(null);        //获取新图片的BufferedImage实例        BufferedImage newBufferedImage = new BufferedImage(width, height,                BufferedImage.TYPE_INT_ARGB);        Graphics g = newBufferedImage.getGraphics();        g.drawImage(img, 0, 0, null);        g.dispose();        return newBufferedImage;    }    public static void main(String[] args){        compareImages("1.jpg","2.jpg");    }}