基于Spring Boot实现图片上传/加水印一把梭操作

2022-05-23 10:05:16

文章共 537字，阅读大约需要 2分钟！

概述

很多网站的图片为了版权考虑都加有水印，尤其是那些图片类网站。自己正好最近和图片打交道比较多，因此就探索了一番基于 Spring Boot这把利器来实现从 图片上传 → 图片加水印 的一把梭操作！

注：本文首发于 My Personal Blog：程序羊，欢迎光临小站

本文内容脑图如下：

搭建 Spring Boot基础工程

过程不再赘述了，这里给出 pom中的关键依赖：

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.5</version>
        </dependency>
    </dependencies>

编写文件上传服务

主要就是编写 ImageUploadService 服务

里面仅一个上传图片的方法：uploadImage 方法

    /**
     * 功能：上传图片
     * @param file 文件
     * @param uploadPath 服务器上上传文件的路径
     * @param physicalUploadPath  服务器上上传文件的物理路径
     * @return 上传文件的 URL相对地址
     */
    public String uploadImage( MultipartFile file, String uploadPath, String physicalUploadPath ) {

        String filePath = physicalUploadPath + file.getOriginalFilename();

        try {
            File targetFile=new File(filePath);
            FileUtils.writeByteArrayToFile(targetFile, file.getBytes());
        } catch (IOException e) {
            e.printStackTrace();
        }
        return uploadPath + "/" + file.getOriginalFilename();
    }
}

编写图片加水印服务

编写 ImageWatermarkService 服务

里面就一个主要的 watermarkAdd方法，代码后面写有详细解释

@Service
public class ImageWatermarkService {

    /**
     * imgFile 图像文件
     * imageFileName 图像文件名
     * uploadPath 服务器上上传文件的相对路径
     * realUploadPath 服务器上上传文件的物理路径
     */
    public String watermarkAdd( File imgFile, String imageFileName, String uploadPath, String realUploadPath ) {

        String imgWithWatermarkFileName = "watermark_" + imageFileName;
        OutputStream os = null;

        try {
            Image image = ImageIO.read(imgFile);

            int width = image.getWidth(null);
            int height = image.getHeight(null);

            BufferedImage bufferedImage = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);  // ①
            Graphics2D g = bufferedImage.createGraphics();  // ②
            g.drawImage(image, 0, 0, width,height,null);  // ③

            String logoPath = realUploadPath + "/" + Const.LOGO_FILE_NAME;  // 水印图片地址
            File logo = new File(logoPath);        // 读取水印图片
            Image imageLogo = ImageIO.read(logo);

            int markWidth = imageLogo.getWidth(null);    // 水印图片的宽度和高度
            int markHeight = imageLogo.getHeight(null);

            g.setComposite( AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, Const.ALPHA) );  // 设置水印透明度
            g.rotate(Math.toRadians(-10), bufferedImage.getWidth()/2, bufferedImage.getHeight()/2);  // 设置水印图片的旋转度

            int x = Const.X;
            int y = Const.Y;

            int xInterval = Const.X_INTERVAL;
            int yInterval = Const.Y_INTERVAL;

            double count = 1.5;
            while ( x < width*count ) {  // 循环添加多个水印logo
                y = -height / 2;
                while( y < height*count ) {
                    g.drawImage(imageLogo, x, y, null);  // ④
                    y += markHeight + yInterval;
                }
                x += markWidth + xInterval;
            }

            g.dispose();

            os = new FileOutputStream(realUploadPath + "/" + imgWithWatermarkFileName);
            JPEGImageEncoder en = JPEGCodec.createJPEGEncoder(os); // ⑤
            en.encode(bufferedImage); // ⑥

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if(os!=null){
                try {
                    os.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        return uploadPath + "/" + imgWithWatermarkFileName;
    }

}

代码思路解释如下：

可以对照代码中的标示数字和下面的解释进行理解：

① 创建缓存图片
② 创建绘图工具
③ 将原图绘制到缓存图片
④ 将水印logo绘制到缓存图片
⑤ 创建图像编码工具类
⑥ 编码缓存图像生成目标图片

可见思路清晰易懂！

编写图片上传/处理控制器

我们在该控制器代码中将上述的 图片上传服务 和 图片加水印服务 给用起来：

@RestController
public class WatermarkController {

    @Autowired
    private ImageUploadService imageUploadService;

    @Autowired
    private ImageWatermarkService watermarkService;

    @RequestMapping(value = "/watermarktest", method = RequestMethod.POST)
    public ImageInfo watermarkTest( @RequestParam("file") MultipartFile image ) {

        ImageInfo imgInfo = new ImageInfo();

        String uploadPath = "static/images/";  // 服务器上上传文件的相对路径
        String physicalUploadPath = getClass().getClassLoader().getResource(uploadPath).getPath();  // 服务器上上传文件的物理路径

        String imageURL = imageUploadService.uploadImage( image, uploadPath, physicalUploadPath );
        File imageFile = new File(physicalUploadPath + image.getOriginalFilename() );

        String watermarkAddImageURL = watermarkService.watermarkAdd(imageFile, image.getOriginalFilename(), uploadPath, physicalUploadPath);

        imgInfo.setImageUrl(imageURL);
        imgInfo.setLogoImageUrl(watermarkAddImageURL);
        return imgInfo;
    }
}