Base64: java.lang.IllegalArgumentException: Illegal character

Question

I'm trying to send a confirmation email after user registration. I'm using the JavaMail library for this purpose and the Java 8 Base64 util class.

I'm encoding user emails in the following way:

byte[] encodedEmail = Base64.getUrlEncoder().encode(user.getEmail().getBytes(StandardCharsets.UTF_8)); Multipart multipart = new MimeMultipart(); InternetHeaders headers = new InternetHeaders(); headers.addHeader("Content-type", "text/html; charset=UTF-8"); String confirmLink = "Complete your registration by clicking on following"+ "\n<a href='" + confirmationURL + encodedEmail + "'>link</a>"; MimeBodyPart link = new MimeBodyPart(headers, confirmLink.getBytes("UTF-8")); multipart.addBodyPart(link); 

where confirmationURL is:

private final static String confirmationURL = "http://localhost:8080/project/controller?command=confirmRegistration&ID="; 

And then decoding this in ConfirmRegistrationCommand in such way:

    String encryptedEmail = request.getParameter("ID");      String decodedEmail = new String(Base64.getUrlDecoder().decode(encryptedEmail), StandardCharsets.UTF_8);      RepositoryFactory repositoryFactory = RepositoryFactory             .getFactoryByName(FactoryType.MYSQL_REPOSITORY_FACTORY);     UserRepository userRepository = repositoryFactory.getUserRepository();     User user = userRepository.find(decodedEmail);      if (user.getEmail().equals(decodedEmail)) {         user.setActiveStatus(true);         return Path.WELCOME_PAGE;     } else {         return Path.ERROR_PAGE;     } 

And when I'm trying to decode:

http://localhost:8080/project/controller?command=confirmRegistration&ID=[B@6499375d 

I'm getting java.lang.IllegalArgumentException: Illegal base64 character 5b.

I tried to use basic Encode/Decoder (not URL ones) with no success.

SOLVED:

The problem was the next - in the line:

 String confirmLink = "Complete your registration by clicking on following"+ "\n<a href='" + confirmationURL + encodedEmail + "'>link</a>"; 

I'm calling toString on an array of bytes, so I should do the following:

String encodedEmail = new String(Base64.getEncoder().encode(                 user.getEmail().getBytes(StandardCharsets.UTF_8))); 

Thanks to Jon Skeet and ByteHamster.

Answer 1

Your encoded text is [B@6499375d. That is not Base64, something went wrong while encoding. That decoding code looks good.

Use this code to convert the byte[] to a String before adding it to the URL:

String encodedEmailString = new String(encodedEmail, "UTF-8"); // ... String confirmLink = "Complete your registration by clicking on following"     + "\n<a href='" + confirmationURL + encodedEmailString + "'>link</a>"; 

Answer 2

I encountered this error since my encoded image started with data:image/png;base64,iVBORw0....

This answer led me to the solution:

String partSeparator = ","; if (data.contains(partSeparator)) {   String encodedImg = data.split(partSeparator)[1];   byte[] decodedImg = Base64.getDecoder().decode(encodedImg.getBytes(StandardCharsets.UTF_8));   Path destinationFile = Paths.get("/path/to/imageDir", "myImage.png");   Files.write(destinationFile, decodedImg); } 

That code removes the meta data in front of the Base64-encoded image and passes the Base64 string to Java's Base64.Decoder to get the image as bytes.