How to return a JWTtoken when users registers for the first time in springboot - spring-boot

Question

I pretty new to Springboot with jwt, I need to generate a jwt token when users sign up for the first time and use the token to allow redirect to another page instead of returning user registered successfully message. How can I achieve this? I am able to generate a token when users signin and use the token for authentication. any help will be appreciated.
how am generating on signin method
#PostMapping("/signin")
public ResponseEntity<?> authenticateUser(#Valid #RequestBody LoginRequest loginRequest) {
Authentication authentication = authenticationManager.authenticate(
new UsernamePasswordAuthenticationToken(loginRequest.getUsername(), loginRequest.getPassword()));
SecurityContextHolder.getContext().setAuthentication(authentication);
String jwt = jwtUtils.generateJwtToken(authentication);
UserDetailsImpl userDetails = (UserDetailsImpl) authentication.getPrincipal();
List<String> roles = userDetails.getAuthorities().stream()
.map(item -> item.getAuthority())
.collect(Collectors.toList());
return ResponseEntity.ok(new JwtResponse(jwt,
userDetails.getId(),
userDetails.getUsername(),
userDetails.getEmail(),
roles));
}
my signup method.
#PostMapping("/signup")
public ResponseEntity<?> registerUser(#Valid #RequestBody SignupRequest signUpRequest) {
if (userRepository.existsByUsername(signUpRequest.getUsername())) {
return ResponseEntity
.badRequest()
.body(new MessageResponse("Error: Username is already taken!"));
}
if (userRepository.existsByEmail(signUpRequest.getEmail())) {
return ResponseEntity
.badRequest()
.body(new MessageResponse("Error: Email is already in use!"));
}
// Create new user's account
User user = new User(signUpRequest.getUsername(), signUpRequest.getEmail(),
encoder.encode(signUpRequest.getPassword()),signUpRequest.getFirstname(),
signUpRequest.getSurname(),signUpRequest.getTelephoneno(),
signUpRequest.getWhatsappno());
Set<String> strRoles = signUpRequest.getRole();
Set<Role> roles = new HashSet<>();
if (strRoles == null) {
Role userRole = roleRepository.findByName(ERole.ROLE_USER)
.orElseThrow(() -> new RuntimeException("Error: Role is not found."));
roles.add(userRole);
} else {
strRoles.forEach(role -> {
switch (role) {
case "admin":
Role adminRole = roleRepository.findByName(ERole.ROLE_ADMIN)
.orElseThrow(() -> new RuntimeException("Error: Role is not found."));
roles.add(adminRole);
break;
case "mod":
Role modRole = roleRepository.findByName(ERole.ROLE_MODERATOR)
.orElseThrow(() -> new RuntimeException("Error: Role is not found."));
roles.add(modRole);
break;
default:
Role userRole = roleRepository.findByName(ERole.ROLE_USER)
.orElseThrow(() -> new RuntimeException("Error: Role is not found."));
roles.add(userRole);
}
});
}
user.setRoles(roles);
userRepository.save(user);
return ResponseEntity.ok(new MessageResponse("User registered successfully!"));
//return ResponseEntity.ok(jwt);
}
how can I generate a token when users sign instead of return ResponseEntity.ok(new MessageResponse("User registered successfully!"));