將圖片以Base64編碼儲存 並在頁面顯示

//convert user avatar into byte and keep in session
BufferedImage avatar = ImageIO.read(new File(your file path));
ByteArrayOutputStream bas = new ByteArrayOutputStream();
ImageIO.write(avatar, new FileOperator().getFileExtName(your file path), bas);
//encode for display
String encodedAvatar = Base64.encode(bas.toByteArray());


//Display
String htmlTag = '<img src="data:image/png;base64,"'+encodedAvatar+'/>';