如何在数据库中将图像LONGBLOB从数据库转换为base64编码的字符串？

Question

i have a String longblobimage, that is taken from the mysql database how do i convert it to a base64 String, and how do i know if its already an encoded image or not?

here is my attempt:

 public String checkForEncode(String string) {
    String regex = "^([A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{4}|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{2}==)$";
    if(string.matches(regex)){
        System.out.println("ERROR33:it's a Base64");
        return string;
    }
    String encodedImage = Base64.encodeToString(string.getBytes(), Base64.DEFAULT);
    return encodedImage;
}

so far this doesnt work to me for some reason

Answer 1

What are you importing to get access to

Base64.encodeToString(string.getBytes(), Base64.DEFAULT)

I'm trying to figure out how this is working, but the Base64 doesn't even have a documented static method that takes an encoding type.

You can translate a string to a base64 byteArray, which is how you would probably store the image to a file.

A String in Java is UTF-16 encoded, so storing a Base64 encoded byteArray back into a String doesn't make sense as that changes the encoding again.

byte[] encoded = Base64.encodeBase64(string.getBytes());