/*
    1、圖片上傳的方法
*/
@RequestMapping(value = "/uploadPic", method = RequestMethod.POST)
    @ResponseBody
    public JsonResult upload(@RequestParam("file") MultipartFile[] files){
        Boolean flag = false;
        String[] picArray = {".jpg",".png",".jpeg"};
        JSONArray jsonArray = new JSONArray();
        if
 
 (files != null && files.length > 0) {
            for(MultipartFile multipartFile : files){
                if (multipartFile == null || multipartFile.isEmpty()) {
                    return new JsonResult(false, "檔案不存在");
                }

                String originalFilename = multipartFile.getOriginalFilename();
                for
 
 (String suffix : picArray) {
                    if(StringUtils.endsWithIgnoreCase(originalFilename, suffix)){
                        flag = true;
                    }
                }

                if(!flag){
                    return new JsonResult(false, "圖片格式不正確，圖片只支援jpg,png,jpeg");
                }

                String extName = originalFilename.substring(originalFilename.lastIndexOf("."
 
) + 1);

                String urlString = "";
                try {
                    /*
                        圖片上傳伺服器之前先對旋轉的圖片進行做修正
                    */
                    byte[] picBytes = rotatePic(multipartFile, extName);
                    //圖片上傳伺服器
                    urlString = dfsService.upload(picBytes, extName);
                    if (null != urlString && urlString.startsWith("HTTP Status ")) {
                        urlString = "";
                    }

                    jsonArray.add(getJsonObject(urlString, (urlString == "" ? urlString : ImgUtils.choiceImgUrl("800X600", urlString))));

                } catch (IOException e) {
                    e.printStackTrace();
                    LOGGER.error("圖片上傳失敗",e);
                    return new JsonResult(false, "圖片上傳失敗");
                }
            }
        }
        return new JsonResult(true, jsonArray);
    }


/*
    2、判斷圖片的是否旋轉
*/

private byte[] rotatePic(MultipartFile multipartFile, String extName) throws IOException{
        ByteArrayOutputStream bos;
        try {
            int orientation=0;
            int angle = 0;
            Metadata metadata = JpegMetadataReader.readMetadata(multipartFile.getInputStream());
            for (Directory dir : metadata.getDirectories()) {
                if (dir != null && dir.containsTag(ExifDirectoryBase.TAG_ORIENTATION)) {
                    orientation = dir.getInt(ExifDirectoryBase.TAG_ORIENTATION);
                    break;
                }
            }
            switch (orientation) {
            case 6:
                angle = 90;
                break;
            case 3:
                angle = 180;
                break;
            case 8:
                angle = 270;
                break;
            default:
                break;
            }
            BufferedImage img = ImageIO.read(multipartFile.getInputStream());
            if(angle != 0){
                //處理旋轉的圖片
                img = RotateImage.Rotate(img, angle);
            }
            bos = new ByteArrayOutputStream();  

            //使用流修改圖片
            ImageIO.write(img, extName, bos);
            //返回新的圖片陣列
            return bos.toByteArray();
        } catch (JpegProcessingException e) {
            return multipartFile.getBytes();
        } catch (MetadataException e) {
            return multipartFile.getBytes();
        } catch (IOException e) {
            return multipartFile.getBytes();
        }
    }

/*
    3、修正圖片的具體工具類（方法）
*/

public class RotateImage {
    public static BufferedImage Rotate(Image src, int angel) {
        int src_width = src.getWidth(null);
        int src_height = src.getHeight(null);
        // calculate the new image size
        Rectangle rect_des = CalcRotatedSize(new Rectangle(new Dimension(src_width, src_height)), angel);

        BufferedImage res = null;
        res = new BufferedImage(rect_des.width, rect_des.height, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = res.createGraphics();
        // transform
        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);
        return res;
    }

    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 Rectangle(new Dimension(des_width, des_height));
    }
}

/*
    4、依賴

    <dependency>
        <groupId>com.drewnoakes</groupId>
        <artifactId>metadata-extractor</artifactId>
        <version>2.8.1</version>
    </dependency>

*/