截取视频中的图片

#将接收到的 MultipartFile 转为File
/**
* 上传视频，截取图片，并将图片上传，返回图片地址值
*/
@PostMapping("/avg/getImg")
public Result getImg(MultipartFile file) {
File toFile = null;
try {
long size = file.getSize();
if (size > 1024 * 1024 * 10) {
return new Result(false, 9, “视频过大，不能超过10M”);
}

            if (file.equals("") || file.getSize() <= 0) {
                file = null;
            } else {
                InputStream ins = null;
                ins = file.getInputStream();
                toFile = new File(file.getOriginalFilename());
                OutputStream os = new FileOutputStream(toFile);
                int bytesRead = 0;
                byte[] buffer = new byte[8192];
                while ((bytesRead = ins.read(buffer, 0, 8192)) != -1) {
                    os.write(buffer, 0, bytesRead);
                }
                os.close();
                ins.close();
                //释放流
                ins.close();
            }
            return JavacvUtil.avGetImg(toFile);
        } catch (Exception e) {
            return new Result(false, 3, "凉了");
        } finally {
            //删除临时文件
            if (toFile != null) {
                File del = new File(toFile.toURI());
                //删除临时文件
                del.delete();
            }
        }
    }

##截取图片并上传到服务器
/**
* 传过来一个视频file返回一个图片路径
*/
public static Result avGetImg(File toFile) throws IOException {
// todo 截图开始
Random random = new Random();
String val = String.valueOf(random.nextInt(99) + 1);//生成第一个数字，不能为0
//定义截过图存放的路径
String imgUrl = “src/main/resources/static/files/a” + val + “.jpg”;
long start = System.currentTimeMillis();
File targetFile = new File(imgUrl);

    @SuppressWarnings("resource")
    FFmpegFrameGrabber ff = new FFmpegFrameGrabber(toFile);
    ff.start();
    int lenght = ff.getLengthInFrames();
    int i = 0;
    Frame f = null;
    while (i < lenght) {
        // 过滤前5帧，避免出现全黑的图片，依自己情况而定
        f = ff.grabFrame();
        if ((i > 48) && (f.image != null)) {
            break;
        }
        i++;
    }
    // IplImage img = f.image;
    int owidth = f.imageWidth;
    int oheight = f.imageHeight;
    // 对截取的帧进行等比例缩放
    int width = 300;
    int height = (int) (((double) width / owidth) * oheight);
    Java2DFrameConverter converter = new Java2DFrameConverter();
    BufferedImage fecthedImage = converter.getBufferedImage(f);
    BufferedImage bi = new BufferedImage(width, height,
            BufferedImage.TYPE_3BYTE_BGR);
    bi.getGraphics().drawImage(
            fecthedImage.getScaledInstance(width, height,
                    Image.SCALE_SMOOTH), 0, 0, null);
    ImageIO.write(bi, "jpg", targetFile);
    ff.stop();
    System.out.println(System.currentTimeMillis() - start);
    //截取完成开始上传图片
    File img = new File(imgUrl);
    //将file转为MultipartFile
    FileInputStream fileInput = new FileInputStream(img);
    MultipartFile toMultipartFile = new MockMultipartFile("file", img.getName(), "text/plain", IOUtils.toByteArray(fileInput));
    toMultipartFile.getInputStream();

    String imageName = toMultipartFile.getOriginalFilename();
    String extName = imageName.substring(imageName.lastIndexOf(".") + 1);
    FastDfsUtil fastDfsUtil = new FastDfsUtil();
    FastDfsFile fastDfsFile = null;
    try {
        fastDfsFile = new FastDfsFile(imageName, toMultipartFile.getBytes(), extName);
        String url = fastDfsUtil.uploadImage(fastDfsFile);
        return new Result(true, 0, url);
    } catch (Exception e) {
        e.printStackTrace();
        return new Result(false, 2, "截图后上传图片出现问题");
    }
}

    <dependency>
        <groupId>org.bytedeco</groupId>
        <artifactId>javacv</artifactId>
        <version>1.4.1</version>
    </dependency>
    <dependency>
        <groupId>org.bytedeco</groupId>
        <artifactId>javacpp</artifactId>
        <version>1.4.1</version>
    </dependency>
    <dependency>
        <groupId>org.bytedeco.javacpp-presets</groupId>
        <artifactId>opencv-platform</artifactId>
        <version>3.4.1-1.4.1</version>
    </dependency>
    <dependency>
        <groupId>org.bytedeco.javacpp-presets</groupId>
        <artifactId>ffmpeg-platform</artifactId>
        <version>3.4.2-1.4.1</version>
    </dependency>
    <!--iowtils-->
    <dependency>
        <groupId>com.jwebmp</groupId>
        <artifactId>commons-io</artifactId>
        <version>0.63.0.61</version>
    </dependency>
     <!--File转MultipartFile时使用了 -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-mock</artifactId>
        <version>2.0.8</version>
    </dependency>