java 圖片相關之類型轉換,壓縮,base64編碼

1.MultipartFile,BufferedImage,File,Image,的轉換

   1)file --> MultipartFile

        File file = new File("F:/test_used_url/ocr/originalPic/111.jpg");
        FileInputStream in_file = new FileInputStream(file)
        MultipartFile multi = new MockMultipartFile("1.jpg", in_file);

  2)MultipartFile --> BufferedImage -->Image

     InputStream in = picture.getInputStream();
     BufferedImage bufferedImage = ImageIO.read(in);

     Image image = bufferedImage.getScaledInstance(80, (int) (80 * ((float) (bufferedImage.getWidth() / bufferedImage.getHeight()))), Image.SCALE_SMOOTH);

2.圖片壓縮:

參數類型MultipartFile 輸出BufferedImage ;

public static BufferedImage compressPic(MultipartFile picture) throws IOException {
        InputStream in = picture.getInputStream();
        BufferedImage bufferedImage = ImageIO.read(in);
        Image image = bufferedImage.getScaledInstance(80, (int) (80 * ((float) (bufferedImage.getWidth() /              bufferedImage.getHeight()))), Image.SCALE_SMOOTH);                    
        BufferedImage outputImage = new BufferedImage(80, (int) (80 * ((float) (bufferedImage.getWidth() / bufferedImage.getHeight()))), BufferedImage.TYPE_INT_RGB);
        outputImage.getGraphics().drawImage(image, 0, 0, null);
        // ImageIO.write(outputImage, "jpg", new File("F:/test_used_url/ocr/originalPic/11111.jpg"));
        return outputImage;
    }

3.Base64編碼

public static String base64(MultipartFile pic_mpFile) throws IOException {
        String baseStr = null;
        InputStream in = pic_mpFile.getInputStream();// -->輸入流
        BufferedImage bi = ImageIO.read(in);// -->bufferedImage
        ByteArrayOutputStream bo = new ByteArrayOutputStream();
        ImageIO.write(bi, "jpg", bo);// 寫入字節輸出流
        BASE64Encoder base64 = new BASE64Encoder();
        baseStr = base64.encode(bo.toByteArray());// -->轉base64編碼
        return baseStr;
    }