JWT Token

[hazartilirot]

Well, I'm not positive about issuing JWT to a user who has been just signed up regardless of error:

To my mind we need to get a token and only then submit a profile to our database

 public ResponseEntity<?> registerCustomer(
            @Valid @RequestBody CustomerDto customerDto
    ) {
        var token = jwtUtil.issueToken(customerDto.email(), "ROLE_USER");
        
        customerService.addCustomer(customerDto);

        return ResponseEntity.ok()
                             .header(HttpHeaders.AUTHORIZATION, token)
                             .build();
    }

then I suggest add a couple of extra lines into your application.yml file

jwt:
  token:
    expires:
      minutes: 60
  secret:
    key: placewhateverkeyyoulikebutmakesureitislongenough_placewhateverkeyyoulikebutmakesureitislongenough_placewhateverkeyyoulikebutmakesureitislongenough_

and here is my jwtUtil.java

@Service
public class JwtUtil {

    private final Environment env;

    public JwtUtil(Environment env) {
        this.env = env;
    }

    public String issueToken(String subject) {
        return issueToken(subject, Map.of());
    }

    public String issueToken(String subject, String ...scopes) {
        return issueToken(subject, Map.of("scopes", scopes));
    }

    public String issueToken(
            String subject,
            Map<String, Object> claims
    ) {
        var currentTime = LocalDateTime.now();
        var expiredWithinMinutes = Integer.parseInt(Objects.requireNonNull(env.getProperty("jwt.token.expires.minutes")));

        return Jwts
                .builder()
                .setClaims(claims)
                .setSubject(subject)
                .setIssuedAt(Date.from(currentTime.atZone(ZoneId.systemDefault()).toInstant()))
                .setExpiration(Date.from(currentTime.plusMinutes(expiredWithinMinutes).atZone(ZoneId.systemDefault()).toInstant()))
                .signWith(getSigningKey(), SignatureAlgorithm.HS512)
                .compact();
    }

    private Key getSigningKey() {
        var secretInBytes = Objects.requireNonNull(env.getProperty("jwt.secret.key")).getBytes();

        byte[] bytesEncoded = Base64.getEncoder().encode(secretInBytes);
        return Keys.hmacShaKeyFor(bytesEncoded);
    }

}

I would also recommend installing Spring CLI, then creating a keystore like :
keytool -genkeypair -alias myKeyAlias -keyalg RSA \ -dname "CN=Local,OU=Local,O=My laptop,L=Hyderabad,S=Telangana,C=India" \ -keypass keyPassword -keystore server.jks -storepass storePassword

then encrypt our secret and use {cipher} instead.... but why bother?