public static void changeAlpha(String oldPath, String newPath, byte alpha) throws IOException {
        changeAlpha(new FileInputStream(oldPath), new FileOutputStream(newPath), alpha);
    }
public static void changeAlpha ( String oldPath , String newPath , byte alpha ) throws IOException { changeAlpha ( new FileInputStream ( oldPath ) , new FileOutputStream ( newPath ) , alpha ) ; }
更改图片alpha值

@param oldPath 图片本地路径
@param newPath 更改alpha值后的图片保存路径
@param alpha   要设置的alpha值
@throws IOException IOException