Table of Contents
1. Overview
In this article, we’ll implement a basic registration process with Spring Security. This is building on top of concepts explored in the previous article, where we looked at login.
The goal here is to add a full registration process that allows a user to sign up, validates, and persists user data.
2. The Registration Page
First – let’s implement a simple registration page displaying the following fields:
- name (first and last name)
- password (and password confirmation field)
The following example shows a simple registration.html page:
Example 2.1.
<html>
<body>
<h1 th:text="#{label.form.title}">form</h1>
<form action="/" th:object="${user}" method="POST" enctype="utf8">
<div>
<label th:text="#{label.user.firstName}">first</label>
<input th:field="*{firstName}"/>
<p th:each="error: ${#fields.errors('firstName')}"
th:text="${error}">Validation error</p>
</div>
<div>
<label th:text="#{label.user.lastName}">last</label>
<input th:field="*{lastName}"/>
<p th:each="error : ${#fields.errors('lastName')}"
th:text="${error}">Validation error</p>
</div>
<div>
<label th:text="#{label.user.email}">email</label>
<input type="email" th:field="*{email}"/>
<p th:each="error : ${#fields.errors('email')}"
th:text="${error}">Validation error</p>
</div>
<div>
<label th:text="#{label.user.password}">password</label>
<input type="password" th:field="*{password}"/>
<p th:each="error : ${#fields.errors('password')}"
th:text="${error}">Validation error</p>
</div>
<div>
<label th:text="#{label.user.confirmPass}">confirm</label>
<input type="password" th:field="*{matchingPassword}"/>
</div>
<button type="submit" th:text="#{label.form.submit}">submit</button>
</form>
<a th:href="@{/login.html}" th:text="#{label.form.loginLink}">login</a>
</body>
</html>
3. The User DTO Object
We need a Data Transfer Object to send all of the registration information to our Spring backend. The DTO object should have all the information we’ll require later on when we create and populate our User object:
public class UserDto {
@NotNull
@NotEmpty
private String firstName;
@NotNull
@NotEmpty
private String lastName;
@NotNull
@NotEmpty
private String password;
private String matchingPassword;
@NotNull
@NotEmpty
private String email;
// standard getters and setters
}
Notice we used standard javax.validation annotations on the fields of the DTO object. Later on, we’re going to also implement our own custom validation annotations to validate the format of the email address as well as for the password confirmation. (see Section 5)
4. The Registration Controller
A Sign-Up link on the login page will take the user to the registration page. This back end for that page lives in the registration controller and is mapped to “/user/registration”:
Example 4.1. – The showRegistration Method
@GetMapping("/user/registration")
public String showRegistrationForm(WebRequest request, Model model) {
UserDto userDto = new UserDto();
model.addAttribute("user", userDto);
return "registration";
}
When the controller receives the request “/user/registration”, it creates the new UserDto object that will back the registration form, binds it, and returns – pretty straightforward.
5. Validating Registration Data
Next – let’s look at the validations that the controller will perform when registering a new account:
- All required fields are filled (No empty or null fields)
- The email address is valid (well-formed)
- The password confirmation field matches the password field
- The account doesn’t already exist
5.1. The Built-In Validation
For the simple checks, we’ll use the out of the box bean validation annotations on the DTO object – annotations like @NotNull, @NotEmpty, etc.
To trigger the validation process, we’ll simply annotate the object in the controller layer with the @Valid annotation:
public ModelAndView registerUserAccount(@ModelAttribute("user") @Valid UserDto userDto,
HttpServletRequest request, Errors errors) {
//...
}
5.2. Custom Validation to Check Email Validity
Next – let’s validate the email address and make sure it’s well-formed. We’re going to be building a custom validator for that, as well as a custom validation annotation – let’s call that @ValidEmail.
A quick side note here – we’re rolling our own custom annotation instead of Hibernate’s @Email because Hibernate considers the old intranet addresses format: myaddress@myserver as valid (see Stackoverflow article), which is no good.
Here’s the email validation annotation and the custom validator:
Example 5.2.1. – The Custom Annotation for Email Validation
@Target({TYPE, FIELD, ANNOTATION_TYPE})
@Retention(RUNTIME)
@Constraint(validatedBy = EmailValidator.class)
@Documented
public @interface ValidEmail {
String message() default "Invalid email";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
Note that we have defined the annotation at the FIELD level – since that’s where it applies conceptually.
Example 5.2.2. – The Custom EmailValidator:
public class EmailValidator
implements ConstraintValidator<ValidEmail, String> {
private Pattern pattern;
private Matcher matcher;
private static final String EMAIL_PATTERN = "^[_A-Za-z0-9-+]+
(.[_A-Za-z0-9-]+)*@" + "[A-Za-z0-9-]+(.[A-Za-z0-9]+)*
(.[A-Za-z]{2,})$";
@Override
public void initialize(ValidEmail constraintAnnotation) {
}
@Override
public boolean isValid(String email, ConstraintValidatorContext context){
return (validateEmail(email));
}
private boolean validateEmail(String email) {
pattern = Pattern.compile(EMAIL_PATTERN);
matcher = pattern.matcher(email);
return matcher.matches();
}
}
Let’s now use the new annotation on our UserDto implementation:
@ValidEmail @NotNull @NotEmpty private String email;
5.3. Using Custom Validation for Password Confirmation
We also need a custom annotation and validator to make sure that the password and matchingPassword fields match up:
Example 5.3.1. – The Custom Annotation for Validating Password Confirmation
@Target({TYPE,ANNOTATION_TYPE})
@Retention(RUNTIME)
@Constraint(validatedBy = PasswordMatchesValidator.class)
@Documented
public @interface PasswordMatches {
String message() default "Passwords don't match";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
Notice that the @Target annotation indicates that this is a TYPE level annotation. This is because we need the entire UserDto object to perform the validation.
The custom validator that will be called by this annotation is shown below:
Example 5.3.2. The PasswordMatchesValidator Custom Validator
public class PasswordMatchesValidator
implements ConstraintValidator<PasswordMatches, Object> {
@Override
public void initialize(PasswordMatches constraintAnnotation) {
}
@Override
public boolean isValid(Object obj, ConstraintValidatorContext context){
UserDto user = (UserDto) obj;
return user.getPassword().equals(user.getMatchingPassword());
}
}
Now, the @PasswordMatches annotation should be applied to our UserDto object:
@PasswordMatches
public class UserDto {
//...
}
All custom validations are of course evaluated along with all standard annotations when the entire validation process runs.
5.4. Check That the Account Doesn’t Already Exist
The fourth check we’ll implement is verifying that the email account doesn’t already exist in the database.
This is performed after the form has been validated and it’s done with the help of the UserService implementation.
Example 5.4.1. – The Controller’s registerUserAccount Method Calls the UserService Object
@PostMapping("/user/registration")
public ModelAndView registerUserAccount(
@ModelAttribute("user") @Valid UserDto userDto,
HttpServletRequest request,
Errors errors) {
try {
User registered = userService.registerNewUserAccount(userDto);
} catch (UserAlreadyExistException uaeEx) {
mav.addObject("message", "An account for that username/email already exists.");
return mav;
}
// rest of the implementation
}
Example 5.4.2. – UserService Checks for Duplicate Emails
@Service
@Transactional
public class UserService implements IUserService {
@Autowired
private UserRepository repository;
@Override
public User registerNewUserAccount(UserDto userDto) throws UserAlreadyExistException {
if (emailExist(userDto.getEmail())) {
throw new UserAlreadyExistException("There is an account with that email address: "
+ userDto.getEmail());
}
// the rest of the registration operation
}
private boolean emailExist(String email) {
return userRepository.findByEmail(email) != null;
}
}
The UserService relies on the UserRepository class to check if a user with a given email address already exists in the database.
Now – the actual implementation of the UserRepository in the persistence layer isn’t relevant for the current article. One quick way is, of course, to use Spring Data to generate the repository layer.
6. Persisting Data and Finishing-Up Form Processing
Finally – let’s implement the registration logic in our controller layer:
Example 6.1.1. – The RegisterAccount Method in the Controller
@PostMapping("/user/registration")
public ModelAndView registerUserAccount(
@ModelAttribute("user") @Valid UserDto userDto,
HttpServletRequest request,
Errors errors) {
try {
User registered = userService.registerNewUserAccount(userDto);
} catch (UserAlreadyExistException uaeEx) {
mav.addObject("message", "An account for that username/email already exists.");
return mav;
}
return new ModelAndView("successRegister", "user", userDto);
}
Things to notice in the code above:
- The controller is returning a ModelAndView object which is the convenient class for sending model data (user) tied to the view.
- The controller will redirect to the registration form if there are any errors set at validation time.
7. The UserService – Register Operation
Let’s finish the implementation of the registration operation in the UserService:
Example 7.1. The IUserService Interface
public interface IUserService {
User registerNewUserAccount(UserDto userDto);
}
Example 7.2. – The UserService Class
@Service
@Transactional
public class UserService implements IUserService {
@Autowired
private UserRepository repository;
@Override
public User registerNewUserAccount(UserDto userDto) throws UserAlreadyExistException {
if (emailExists(userDto.getEmail())) {
throw new UserAlreadyExistException("There is an account with that email address: "
+ userDto.getEmail());
}
User user = new User();
user.setFirstName(userDto.getFirstName());
user.setLastName(userDto.getLastName());
user.setPassword(userDto.getPassword());
user.setEmail(userDto.getEmail());
user.setRoles(Arrays.asList("ROLE_USER"));
return repository.save(user);
}
private boolean emailExists(String email) {
return userRepository.findByEmail(email) != null;
}
}
8. Loading User Details for Security Login
In our previous article, login was using hard-coded credentials. Let’s change that and use the newly registered user information and credentials. We’ll implement a custom UserDetailsService to check the credentials for login from the persistence layer.
8.1. The Custom UserDetailsService
Let’s start with the custom user details service implementation:
@Service
@Transactional
public class MyUserDetailsService implements UserDetailsService {
@Autowired
private UserRepository userRepository;
public UserDetails loadUserByUsername(String email) throws UsernameNotFoundException {
User user = userRepository.findByEmail(email);
if (user == null) {
throw new UsernameNotFoundException("No user found with username: " + email);
}
boolean enabled = true;
boolean accountNonExpired = true;
boolean credentialsNonExpired = true;
boolean accountNonLocked = true;
return new org.springframework.security.core.userdetails.User(
user.getEmail(), user.getPassword().toLowerCase(), enabled, accountNonExpired,
credentialsNonExpired, accountNonLocked, getAuthorities(user.getRoles()));
}
private static List<GrantedAuthority> getAuthorities (List<String> roles) {
List<GrantedAuthority> authorities = new ArrayList<>();
for (String role : roles) {
authorities.add(new SimpleGrantedAuthority(role));
}
return authorities;
}
}
8.2. Enable the New Authentication Provider
To enable the new user service in the Spring Security configuration – we simply need to add a reference to the UserDetailsService inside the authentication-manager element and add the UserDetailsService bean:
Example 8.2.- The Authentication Manager and the UserDetailsService
<authentication-manager>
<authentication-provider user-service-ref="userDetailsService" />
</authentication-manager>
<beans:bean id="userDetailsService" class="com.maixuanviet.security.MyUserDetailsService" />
Or, via Java configuration:
@Autowired
private MyUserDetailsService userDetailsService;
@Override
protected void configure(AuthenticationManagerBuilder auth) throws Exception {
auth.userDetailsService(userDetailsService);
}
9. Conclusion
And we’re done – a complete and almost production-ready registration process implemented with Spring Security and Spring MVC. Next, we’re going to discuss the process of activating the newly registered account by verifying the email of the new user.
The implementation of this Spring Security REST Tutorial can be found over on GitHub.
