java 使用ImageIO.write如何生成jpeg图像

    public static byte[] wirteJPEGBytes(BufferedImage source){    if(null==source)      throw new NullPointerException();    ByteArrayOutputStream output = new ByteArrayOutputStream();    JPEGImageEncoder jencoder = JPEGCodec.createJPEGEncoder(output);    JPEGEncodeParam param = jencoder.getDefaultJPEGEncodeParam(source);    param.setQuality(0.75f, true);    jencoder.setJPEGEncodeParam(param);    try {      jencoder.encode(source);    } catch (ImageFormatException e) {      throw new RuntimeException(e);    } catch (IOException e) {      throw new RuntimeException(e);    }    return output.toByteArray();    }