图片上传功能

springboot控制层代码如下：

@PostMapping("upload")
  public Result<String> uploadImage(MultipartFile file){
      String imagePath = UploadImageUtil.uploadImage(file);
  }

图片上传函数

/**
 * 上传图片函数
 * @param file 图片文件
 * @return
 */
public static String uploadImage(MultipartFile file){
    // 获取唯一的uuid
    String uuid = UUID.randomUUID().toString().replace("-", "").toLowerCase();
    try {
        // 获取图片存储的完整路径
        String path1 = URLDecoder.decode((ResourceUtils.getURL("classpath:").getPath()+"static/img/"), System.getProperty("file.encoding"));
        String imagePath = path1 + uuid + ".jpg";
        // 获取要上传图片的目录，同时解码
        File imageFolder = new File(URLDecoder.decode(path1, System.getProperty("file.encoding")));
        // new一个图片文件
        File fileImage = new File(imageFolder, uuid + ".jpg");
        if (!fileImage.getParentFile().exists()) {
            // 如果不存在这个目录就创建一个目录
            fileImage.getParentFile().mkdirs();
        }
        file.transferTo(fileImage);
        BufferedImage img = ImageUtil.change2jpg(fileImage);
        ImageIO.write(img, "jpg", fileImage);
        // 返回图片的相对路径
        return "/img/" + uuid + ".jpg";
    }catch (Exception e){
        e.printStackTrace();
        // 上传图片失败就返回一个长度为0的空字符串
        return "";
    }
}

ImageUtil转换函数

public class ImageUtil {

    public static BufferedImage change2jpg(File f) {
        try {
            Image i = Toolkit.getDefaultToolkit().createImage(f.getAbsolutePath());
            PixelGrabber pg = new PixelGrabber(i, 0, 0, -1, -1, true);
            pg.grabPixels();
            int width = pg.getWidth(), height = pg.getHeight();
            final int[] RGB_MASKS = { 0xFF0000, 0xFF00, 0xFF };
            final ColorModel RGB_OPAQUE = new DirectColorModel(32, RGB_MASKS[0], RGB_MASKS[1], RGB_MASKS[2]);
            DataBuffer buffer = new DataBufferInt((int[]) pg.getPixels(), pg.getWidth() * pg.getHeight());
            WritableRaster raster = Raster.createPackedRaster(buffer, width, height, width, RGB_MASKS, null);
            BufferedImage img = new BufferedImage(RGB_OPAQUE, raster, false, null);
            return img;
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return null;
        }
    }

    public static void resizeImage(File srcFile, int width,int height, File destFile) {
        try {
            if(!destFile.getParentFile().exists()) {
                destFile.getParentFile().mkdirs();
            }
            Image i = ImageIO.read(srcFile);
            i = resizeImage(i, width, height);
            ImageIO.write((RenderedImage) i, "jpg", destFile);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public static Image resizeImage(Image srcImage, int width, int height) {
        try {

            BufferedImage buffImg = null;
            buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            buffImg.getGraphics().drawImage(srcImage.getScaledInstance(width, height, Image.SCALE_SMOOTH), 0, 0, null);

            return buffImg;
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }

}