Java上传图片角度旋转（无损）

1、旋转工具类

package com.ruoyi.common.file.util;

/**
 * @author ：wt
 * @date ：Created in 2022/6/29 22:44
 * @description：
 * @modified By：
 */
import java.awt.*;
import java.awt.image.BufferedImage;

/**
 * 图片旋转工具类
 */
public class RotateImage {

    /**
     * 对图片进行旋转
     *
     * @param src   被旋转图片
     * @param angel 旋转角度
     * @return 旋转后的图片
     */
    public static BufferedImage Rotate(Image src, int angel) {
        int src_width = src.getWidth(null);
        int src_height = src.getHeight(null);
        // 计算旋转后图片的尺寸
        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();
        // 进行转换
        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;
    }

    /**
     * 计算旋转后的图片
     *
     * @param src   被旋转的图片
     * @param angel 旋转角度
     * @return 旋转后的图片
     */
    public static Rectangle CalcRotatedSize(Rectangle src, int angel) {
        // 如果旋转的角度大于90度做相应的转换
        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));
    }
}

2、使用

•  思路：上传后，根据记录下的实际图片存储位置，通过旋转工具旋转完后替换

  
  /**
  * 通用上传请求
  */
  @PostMapping("/common/upload")
  public AjaxResult uploadFile(MultipartFile file,Integer modelType) throws Exception
  {
  try
  {
  // 上传文件路径
  String filePath = RuoYiConfig.getUploadPath();
  // 上传并返回新文件名称
  String fileName = FileUploadUtils.upload(filePath, file);
  String url = serverConfig.getUrl() + fileName;//下载是因为需要/prod-api/所以加上能下载,用于部署服务器。本地加上报错
  AjaxResult ajax = AjaxResult.success();
  ajax.put("fileName", fileName);
  ajax.put("url", url);
  //app签字图片旋转
  if(modelType == 1){
  BufferedImage src = ImageIO.read(file.getInputStream());
  //顺时针旋转270度
  BufferedImage newImage = RotateImage.Rotate(src, 270);
  String finame = file.getOriginalFilename();
  ImageIO.write(newImage, finame.split("\\.")[1], new File(filePath+fileName.replaceAll("/profile/upload","")));
  }
  return ajax;
  }
  catch (Exception e)
  {
  e.printStackTrace();
  return AjaxResult.error(e.getMessage());
  }
  }