Step by step guide how to create Sign up

Backend Low Level Design 4

About Lesson

Step1: Create a project download and extract and open in intellij using pom file as project

Add the database details in the “src/resources/application.properties” file:

spring.application.name=user
spring.datasource.url = jdbc:mysql://127.0.0.1:3306/auth
spring.datasource.username = root
spring.datasource.password =
spring.jpa.show-sql = true
spring.jpa.hibernate.ddl-auto = create
server.port=8080

Next, start the MySQL Server and create a new schema named “authService”.

Next, create a simple controller to check if everything is working. Create a package named “controllers” and create a “HelloController” class marked with “@RestController“

@RestController

public class HelloController {

@GetMapping(“/hi”)

public String sayHi(){

return “Hi”;

}

Now run the application and check

Next, create a package named “models“. Inside this package, create a class named “BaseModel“. Annotate this class with
“@MappedSuperclass“. Use Lombok to generate getters and setters above the class.

Inside the “BaseModel” class, declare a private variable “id” of type long. Above this variable, annotate it with “@Id” and “@GeneratedValue(strategy = GenerationType.IDENTITY)” to set it as the primary key with auto-increment.

@MappedSuperclass

@Getter

@Setter

public class BaseModel {

@Id

@GeneratedValue(strategy = GenerationType.IDENTITY)

private Long id;

}

Next Crate Class Role

@Entity(name = “role_user”)

@Getter

@Setter

public class Role extends BaseModel{

private String name;

}

Next Create class Token

@Entity(name=”user_token”)

@Getter

@Setter

public class Token extends BaseModel {

private String value;

private Date expirydate;

private boolean isDeleted;

@ManyToOne // 1 token can have 1 user and 1 user can have multiple token

private User user;

}

Next Create User

@Entity(name = “user_self”)

@Setter

@Getter

public class User extends BaseModel{

private String name;

private String email;

private String hashedPassword;

// 1 user can have multiple role and 1 role can have multiple user

@ManyToMany

private List<Role> roles;

private boolean isEmailVerified;

}

Next create UserControler in Controllers package

@RestController

public class UserController {

@Autowired

private UserService userService;

@PostMapping(“/signup”)

public User signUp(@RequestBody SignupRequestDto signupRequestDto){

String email = signupRequestDto.getEmail();

String password = signupRequestDto.getPassword();

String name = signupRequestDto.getName();

return userService.signUp(name, email, password);

}

Two things to consider here: we need to create a SignupDto and a UserService. We’ll autowire the UserService to accomplish this. We call the signUp method from the UserService, passing the required data provided by the signupRequestDto.

Next Create a package named “dtos” and inside it, create a class called “SignupRequestDto“

@Getter

@Setter

public class SignupRequestDto {

private String email;

private String password;

private String name;

}

Next, let’s create a package named “services“. Inside this package, we’ll set up a class called “UserService“. Within this class, we’ll autowire the UserRepository and use its findByEmail method within the signUp function. If the method returns an Optional, we’ll check if the user is present. If they are, we’ll throw an error. Otherwise, we’ll create a user with a bcrypt password using bCryptPasswordEncoder and save it to the repository. in order to autowired bCryptPasswordEncoder we have to create a bean because this is third party library which we do it below.

To use bCryptPasswordEncoder we have to add a dependency open Google and search “bcrypt password encoder maven”

<groupId>org.springframework.security</groupId>

<artifactId>spring-security-crypto</artifactId>

</dependency>

open https://mvnrepository.com/artifact/org.springframework.security/spring-security-crypto

click on the latest version like here 6.2.4 copy code and pest in pom file as dependency and click the button on right top button to install dependency

@Service

public class UserService {

@Autowired

private UserRepository userRepository;

@Autowired

private BCryptPasswordEncoder bCryptPasswordEncoder;

public User signUp(String name, String email, String password){

// skipping email verification part here.

Optional<User> optionalUser = userRepository.findByEmail(email);

if(optionalUser.isPresent()){

// throw user is already present

}

User user = new User();

user.setEmail(email);

user.setName(name);

user.setHashedPassword(bCryptPasswordEncoder.encode(password));

return userRepository.save(user);

}

Next, within the “repositories” package, create a class called “UserRepository“. Annotate this class with “@Repository“. Extend JpaRepository<User, Long>

@Repository

public interface UserRepository extends
JpaRepository<User, Long> {

}

Next, let’s create a package called “config“. Inside this package, create a class named “Configuration“. Above this class, annotate it with “@org.springframework.context.annotation.Configuration“. Inside the class, create a method (its name can be anything) and annotate this method with “@Bean“.

The @org.springframework.context.annotation.Configuration annotation in Spring signifies that the class is a configuration class. It’s part of the Spring Framework’s annotation-based configuration approach. When you mark a class with @Configuration, Spring treats it as a source of bean definitions. Essentially, it replaces XML-based configuration.

In simpler terms, it tells Spring that this class contains configurations for the application, such as bean definitions or other setup tasks. This way, Spring can manage these configurations and beans accordingly.

@org.springframework.context.annotation.Configuration

public class Configuration {

@Bean

public BCryptPasswordEncoder bCryptPasswordEncoder(){

return new BCryptPasswordEncoder();

}

Next now open postman

Now, open Postman and select the method as POST. Use the URL http://localhost:8080/signup.
In the body section, select “raw” and then “JSON”.
Provide some data in the body like:

{
“name“: “Sanjay“,
“email“:”sa****@gm***.com“,
“password“:”password123“
}

Click on “Send“. If this works, it will return a “User” as a response.

Step1: Create a project download and extract and open in intellij using pom file as project

Next Crate Class Role

Next Create class Token

Next Create User

Next create UserControler in Controllers package

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