在圣品上传时往往需要生成一张预览图（缩略图），如果在非特殊情况下让用户单独上传，会造成工作压力，此时可以用视频中某一帧作为封面图，实现方式如下：

public class ImageUtil {    /**     * 生成截图     * @param filePath 视频文件本地路径     * @param targerFilePath 目标文件夹     * @param targetFileName 目标文件名     * @return 图片文件路径     * @throws Exception     */    public static String randomGrabberFFmpegImage(String filePath, String targerFilePath, String targetFileName)            throws Exception {        System.out.println(filePath);        FFmpegFrameGrabber ff = FFmpegFrameGrabber.createDefault(filePath);        ff.start();        Frame f;        int lenght = ff.getLengthInFrames();        int i = 0;        String path = 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 > 200) && (f.image != null)) {                path = doExecuteFrame(f, targerFilePath, targetFileName);                break;            }            i++;        }        ff.stop();        return path;    }    public static String doExecuteFrame(Frame f, String targerFilePath, String targetFileName) {        if (null ==f ||null ==f.image) {            throw new GlobleException("获取缩略图失败");        }        Java2DFrameConverter converter =new Java2DFrameConverter();        String imageMat ="jpg";        String FileName =targerFilePath + File.separator +targetFileName +"." +imageMat;        BufferedImage bi =converter.getBufferedImage(f);        System.out.println("width:" + bi.getWidth());        System.out.println("height:" + bi.getHeight());        File output =new File(FileName);        try {            ImageIO.write(bi,imageMat,output);        }catch (IOException e) {            throw new GlobleException("缩略图写入文件夹失败");        }        return FileName;    }    public static void main(String[] args) throws Exception {        String s = randomGrabberFFmpegImage("/home/xiao/IMG_3077.mp4", "/home/xiao", "213");        System.out.println(s);    }}