java在上传视频时生成预览图

 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);
}
}