java后台解决手机端上传图片自己旋转的问题

来源：互联网发布：mac 移动硬盘 win7 编辑：程序博客网时间：2024/06/05 03:06

我们用手机网页上传图片时,经常会遇见图片被旋转了的问题.用以下的方法就可以将图片上传时拨乱反正,给重新调整回来.

public class PicUtil {

    /**
     * 获取图片正确显示需要旋转的角度（顺时针）
     * @return
     */
    public static int getRotateAngleForPhoto(String filePath){

        File file = new File(filePath);

        int angle = 0;

        Metadata metadata;
        try {
            metadata = JpegMetadataReader.readMetadata(file);
            Directory directory = metadata.getDirectory(ExifDirectory.class);
                if(directory.containsTag(ExifDirectory.TAG_ORIENTATION)){

                  // Exif信息中方向　　
                   int orientation = directory.getInt(ExifDirectory.TAG_ORIENTATION);

                   // 原图片的方向信息
                   if(6 == orientation ){
                       //6旋转90
                       angle = 90;
                   }else if( 3 == orientation){
                      //3旋转180
                       angle = 180;
                   }else if( 8 == orientation){
                      //8旋转90
                       angle = 270;
                   }
                }
        } catch (JpegProcessingException e) {
            e.printStackTrace();
        } catch (MetadataException e) {
            e.printStackTrace();
        }

        return angle;
    }

    /**
     * 旋转手机照片
     * @return
     */
    public static String rotatePhonePhoto(String fullPath, int angel){

       if(angel == 0){
           return fullPath;
       }

        BufferedImage src;
        try {
            src = ImageIO.read(new File(fullPath));

            int src_width = src.getWidth(null);
            int src_height = src.getHeight(null);

            Rectangle rect_des = CalcRotatedSize(new Rectangle(new Dimension(src_width, src_height)), angel);

            BufferedImage res = new BufferedImage(rect_des.width, rect_des.height,BufferedImage.TYPE_INT_RGB);
            Graphics2D g2 = res.createGraphics();

            g2.translate((rect_des.width - src_width) / 2,
                    (rect_des.height - src_height) / 2);
            g2.rotate(Math.toRadians(angel), src_width / 2, src_height / 2);

            g2.drawImage(src, null, null);

            ImageIO.write(res, "jpg", new File(fullPath));

        } catch (IOException e) {

            e.printStackTrace();
        }

        return fullPath;

    }

    public static Rectangle CalcRotatedSize(Rectangle src, int angel) {
        // if angel is greater than 90 degree, we need to do some conversion
        if (angel >= 90) {
            if(angel / 90 % 2 == 1){
                int temp = src.height;
                src.height = src.width;
                src.width = temp;
            }
            angel = angel % 90;
        }

        double r = Math.sqrt(src.height * src.height + src.width * src.width) / 2;
        double len = 2 * Math.sin(Math.toRadians(angel) / 2) * r;
        double angel_alpha = (Math.PI - Math.toRadians(angel)) / 2;
        double angel_dalta_width = Math.atan((double) src.height / src.width);
        double angel_dalta_height = Math.atan((double) src.width / src.height);

        int len_dalta_width = (int) (len * Math.cos(Math.PI - angel_alpha
                - angel_dalta_width));
        int len_dalta_height = (int) (len * Math.cos(Math.PI - angel_alpha
                - angel_dalta_height));
        int des_width = src.width + len_dalta_width * 2;
        int des_height = src.height + len_dalta_height * 2;
        return new java.awt.Rectangle(new Dimension(des_width, des_height));
    }

}

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