java在上傳視頻時生成預覽圖

在聖品上傳時每每須要生成一張預覽圖（縮略圖），若是在非特殊狀況下讓用戶單獨上傳，會形成工做壓力，此時能夠用視頻中某一幀做爲封面圖，實現方式以下：

public class ImageUtil {

    /**
     * 生成截圖
     * @param filePath 視頻文件本地路徑
     * @param targerFilePath 目標文件夾
     * @param targetFileName 目標文件名
     * @return 圖片文件路徑
     * @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) {
            // 過濾前5幀，避免出現全黑的圖片，依本身狀況而定
            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("獲取縮略圖失敗");
        }
        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("縮略圖寫入文件夾失敗");
        }
        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);
    }
}