Return success from api as true or false om Spring REST API

I am pretty new to Springboot. How can I configure my Springboot API to return the JSON response below from my login or register endpoints?. How I can return true – successful response? And also for example if there is a code exception into code processing how can I return false as the success JSON response?

{
  'message': "user created successfully",
  'success' : true or false depending on the state of the request
}

What I have so far: My login API

@PostMapping("/signin")
    public ResponseEntity<?> authenticateUser(@Valid @RequestBody LoginRequest loginRequest) {

        if (!userRepository.existsByUsername(loginRequest.getUsername()) {
            return ResponseEntity
                    .badRequest()
                    .body(new MessageResponse("Invalid Login credentials!"));
        }else{
            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 API:

    @PostMapping("/signup")
    public ResponseEntity<?> registerUser(@Valid @RequestBody SignupRequest signUpRequest) {

        if (userRepository.existsByUsername(signUpRequest.getUsername())) {
            return ResponseEntity
                    .badRequest()
                    .body(new MessageResponse("Email is already in use!"));
        }

        if (userRepository.existsByEmail(signUpRequest.getEmail())) {
            return ResponseEntity
                    .badRequest()
                    .body(new MessageResponse("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("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("Role is not found."));
                    roles.add(adminRole);

                    break;
                case "mod":
                    Role modRole = roleRepository.findByName(ERole.ROLE_MODERATOR)
                            .orElseThrow(() -> new RuntimeException("Role is not found."));
                    roles.add(modRole);

                    break;
                default:
                    Role userRole = roleRepository.findByName(ERole.ROLE_USER)
                            .orElseThrow(() -> new RuntimeException("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);
    }
}

MessageResponse class

public class MessageResponse {
    private String message;

    public MessageResponse(String message) {
        this.message = message;
      }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }
}

Answer

you didn’t post the code for MessageResponse, so if it’s your class you can add the boolean field to it and the ResponseEntity<?> wrapper can wrap this object that has 2 fields. another option is to use @ResponseBody annotation instead of ResponseEntity. please read more Here