In this tutorial, we will create a user authentication system using JSON Web Tokens (JWT) with Spring Boot 3 for the backend and Vue.js 3.4 for the frontend. We will use Spring Security 6 to secure the application and Vue.js to handle the user interface.

Prerequisites

Before we start, ensure you have the following:

Java Development Kit (JDK) installed
Apache Maven installed
Node.js and npm installed
An IDE (such as IntelliJ IDEA, Eclipse, or VS Code) installed

Step 1: Setting Up the Spring Boot Project

1.1 Create a Spring Boot Project

Open Spring Initializr:
- Go to Spring Initializr in your web browser.
Configure Project Metadata:
- Project: Maven Project
- Language: Java
- Spring Boot: Select the latest version of Spring Boot 3
- Group: com.example
- Artifact: jwt-authentication
- Name: jwt-authentication
- Description: JWT Authentication with Spring Boot and Vue.js
- Package Name: com.example.jwtauthentication
- Packaging: Jar
- Java Version: 17 (or your preferred version)
- Click Next.
Select Dependencies:
- On the Dependencies screen, select the dependencies you need:
  - Spring Web
  - Spring Data JPA
  - H2 Database
  - Spring Boot DevTools
  - Spring Security
  - Spring Boot Starter Mail
  - JWT (io.jsonwebtoken:jjwt-api, io.jsonwebtoken:jjwt-impl, io.jsonwebtoken:jjwt-jackson)
- Click Next.
Generate the Project:
- Click Generate to download the project zip file.
- Extract the zip file to your desired location.
Open the Project in Your IDE:

Open your IDE and import the project as a Maven project.

1.2 Maven Dependencies

Here's a pom.xml file for the Spring Boot and JWT authentication tutorial:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>jwt-authentication</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>jwt-authentication</name>
    <description>Full Stack Application with Spring Boot and Vue.js for JWT Authentication</description>
    <packaging>jar</packaging>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.0.6</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <java.version>17</java.version>
        <jjwt.version>0.11.5</jjwt.version>
    </properties>

    <dependencies>
        <!-- Spring Boot dependencies -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>

        <!-- H2 Database -->
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <scope>runtime</scope>
        </dependency>

        <!-- JWT dependencies -->
        <dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt-api</artifactId>
            <version>${jjwt.version}</version>
        </dependency>
        <dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt-impl</artifactId>
            <version>${jjwt.version}</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt-jackson</artifactId> <!-- or jjwt-gson if preferred -->
            <version>${jjwt.version}</version>
            <scope>runtime</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

I suggest using the same JWT dependency versions as the ones used in this tutorial.

1.3 Update `application.properties`

Open the application.properties file located in the src/main/resources directory and add the following configuration:

spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=password

spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
spring.h2.console.enabled=true
spring.jpa.hibernate.ddl-auto=update

# JWT Configuration
jwt.secret=secret
jwt.expiration=3600000

1.4 Create the `User` Entity

In the com.example.jwtauthentication.model package, create a new Java class named User:

package com.example.jwtauthentication.model;

import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;

@Entity
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String firstName;
    private String lastName;
    private String email;
    private String password;

    // Getters and Setters
}

1.5 Create the `UserRepository` Interface

In the com.example.jwtauthentication.repository package, create a new Java interface named UserRepository:

package com.example.jwtauthentication.repository;

import com.example.jwtauthentication.model.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface UserRepository extends JpaRepository<User, Long> {
    User findByEmail(String email);
}

1.6 Create the `UserService` Class

In the com.example.jwtauthentication.service package, create a new Java class named UserService:

package com.example.jwtauthentication.service;

import com.example.jwtauthentication.model.User;
import com.example.jwtauthentication.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.stereotype.Service;

@Service
public class UserService {

    private final UserRepository userRepository;
    private final BCryptPasswordEncoder passwordEncoder;

    @Autowired
    public UserService(UserRepository userRepository, BCryptPasswordEncoder passwordEncoder) {
        this.userRepository = userRepository;
        this.passwordEncoder = passwordEncoder;
    }

    public User saveUser(User user) {
        user.setPassword(passwordEncoder.encode(user.getPassword()));
        return userRepository.save(user);
    }

    public User findByEmail(String email) {
        return userRepository.findByEmail(email);
    }
}

1.7 Create JWT Utility Class

In the com.example.jwtauthentication.util package, create a new Java class named JwtUtil:

package com.example.jwtauthentication.util;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.function.Function;

@Component
public class JwtUtil {

    @Value("${jwt.secret}")
    private String secret;

    @Value("${jwt.expiration}")
    private long expiration;

    public String extractUsername(String token) {
        return extractClaim(token, Claims::getSubject);
    }

    public <T> T extractClaim(String token, Function<Claims, T> claimsResolver) {
        final Claims claims = extractAllClaims(token);
        return claimsResolver.apply(claims);
    }

    private Claims extractAllClaims(String token) {
        return Jwts.parser().setSigningKey(secret).parseClaimsJws(token).getBody();
    }

    public String generateToken(String username) {
        Map<String, Object> claims = new HashMap<>();
        return createToken(claims, username);
    }

    private String createToken(Map<String, Object> claims, String subject) {
        return Jwts.builder().setClaims(claims).setSubject(subject).setIssuedAt(new Date(System.currentTimeMillis()))
                .setExpiration(new Date(System.currentTimeMillis() + expiration))
                .signWith(SignatureAlgorithm.HS256, secret).compact();
    }

    public boolean validateToken(String token, String username) {
        final String extractedUsername = extractUsername(token);
        return (extractedUsername.equals(username) && !isTokenExpired(token));
    }

    private boolean isTokenExpired(String token) {
        return extractExpiration(token).before(new Date());
    }

    public Date extractExpiration(String token) {
        return extractClaim(token, Claims::getExpiration);
    }
}

1.8 Create JWT Authentication Filter

In the com.example.jwtauthentication.filter package, create a new Java class named JwtAuthenticationFilter:

package com.example.jwtauthentication.filter;

import com.example.jwtauthentication.service.UserService;
import com.example.jwtauthentication.util.JwtUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.web.authentication.WebAuthenticationDetailsSource;
import org.springframework.stereotype.Component;
import org.springframework.web.filter.OncePerRequestFilter;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Component
public class JwtAuthenticationFilter extends OncePerRequestFilter {

    @Autowired
    private JwtUtil jwtUtil;

    @Autowired
    private UserService userService;

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
        final String authorizationHeader = request.getHeader("Authorization");

        String username = null;
        String jwt = null;

        if (authorizationHeader != null && authorizationHeader.startsWith("Bearer ")) {
            jwt = authorizationHeader.substring(7);
            username = jwtUtil.extractUsername(jwt);
        }

        if (username != null && SecurityContextHolder.getContext().getAuthentication() == null) {
            UserDetails userDetails = this.userService.loadUserByUsername(username);

            if (jwtUtil.validateToken(jwt, userDetails.getUsername())) {
                UsernamePasswordAuthenticationToken usernamePasswordAuthenticationToken = new UsernamePasswordAuthenticationToken(
                        userDetails, null, userDetails.getAuthorities());
                usernamePasswordAuthenticationToken.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));
                SecurityContextHolder.getContext().setAuthentication(usernamePasswordAuthenticationToken);
            }
        }
        filterChain.doFilter(request, response);
    }
}

1.9 Create Security Configuration

Create a new Java class named SecurityConfig in the com.example.jwtauthentication.config package:

package com.example.jwtauthentication.config;

import com.example.jwtauthentication.filter.JwtAuthenticationFilter;
import com.example.jwtauthentication.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.config.annotation.authentication.configuration.AuthenticationConfiguration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.config.annotation.web.configurers.AbstractHttpConfigurer;
import org.springframework.security.crypto.b

crypt.BCryptPasswordEncoder;
import org.springframework.security.web.SecurityFilterChain;
import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;

@Configuration
@EnableWebSecurity
public class SecurityConfig {

    @Autowired
    private JwtAuthenticationFilter jwtAuthenticationFilter;

    @Autowired
    private UserService userService;

    @Bean
    public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
        http
            .csrf(AbstractHttpConfigurer::disable)
            .authorizeHttpRequests(auth -> auth
                .requestMatchers("/auth/**").permitAll()
                .anyRequest().authenticated()
            )
            .addFilterBefore(jwtAuthenticationFilter, UsernamePasswordAuthenticationFilter.class);

        return http.build();
    }

    @Bean
    public BCryptPasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }

    @Bean
    public AuthenticationManager authenticationManager(AuthenticationConfiguration authenticationConfiguration) throws Exception {
        return authenticationConfiguration.getAuthenticationManager();
    }
}

1.10 Update UserService to Implement UserDetailsService

Update the UserService class to implement UserDetailsService:

package com.example.jwtauthentication.service;

import com.example.jwtauthentication.model.User;
import com.example.jwtauthentication.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.stereotype.Service;

import java.util.Collections;

@Service
public class UserService implements UserDetailsService {

    private final UserRepository userRepository;
    private final BCryptPasswordEncoder passwordEncoder;

    @Autowired
    public UserService(UserRepository userRepository, BCryptPasswordEncoder passwordEncoder) {
        this.userRepository = userRepository;
        this.passwordEncoder = passwordEncoder;
    }

    public User saveUser(User user) {
        user.setPassword(passwordEncoder.encode(user.getPassword()));
        return userRepository.save(user);
    }

    public User findByEmail(String email) {
        return userRepository.findByEmail(email);
    }

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        User user = userRepository.findByEmail(username);
        if (user == null) {
            throw new UsernameNotFoundException("User not found");
        }
        return new org.springframework.security.core.userdetails.User(user.getEmail(), user.getPassword(), Collections.emptyList());
    }
}

1.11 Create the `AuthController` Class

In the com.example.jwtauthentication.controller package, create a new Java class named AuthController:

package com.example.jwtauthentication.controller;

import com.example.jwtauthentication.model.User;
import com.example.jwtauthentication.service.UserService;
import com.example.jwtauthentication.util.JwtUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/auth")
public class AuthController {

    private final UserService userService;
    private final AuthenticationManager authenticationManager;
    private final JwtUtil jwtUtil;

    @Autowired
    public AuthController(UserService userService, AuthenticationManager authenticationManager, JwtUtil jwtUtil) {
        this.userService = userService;
        this.authenticationManager = authenticationManager;
        this.jwtUtil = jwtUtil;
    }

    @PostMapping("/register")
    public User registerUser(@RequestBody User user) {
        return userService.saveUser(user);
    }

    @PostMapping("/login")
    public String loginUser(@RequestBody User user) {
        Authentication authentication = authenticationManager.authenticate(
                new UsernamePasswordAuthenticationToken(user.getEmail(), user.getPassword())
        );
        SecurityContextHolder.getContext().setAuthentication(authentication);
        UserDetails userDetails = userService.loadUserByUsername(user.getEmail());
        return jwtUtil.generateToken(userDetails.getUsername());
    }
}

Step 2: Creating the Frontend with Vue.js

2.1 Set Up Vue Project

Open a terminal and navigate to your workspace directory.

Create a new Vue project using Vue CLI:

npm install -g @vue/cli
vue create vue-frontend

Navigate to the project directory:
```
cd vue-frontend
```

2.2 Install Axios and Bootstrap

Install Axios to make HTTP requests and Bootstrap for styling:

npm install axios bootstrap

2.3 Create Components

Create the necessary components for user registration and login.

2.3.1 Create AuthService.js

Create a new file AuthService.js in the src directory to handle API requests for authentication:

import axios from 'axios';

const API_BASE_URL = "http://localhost:8080/auth";

class AuthService {
    register(user) {
        return axios.post(`${API_BASE_URL}/register`, user);
    }

    login(user) {
        return axios.post(`${API_BASE_URL}/login`, user);
    }
}

export default new AuthService();

2.3.2 Create RegisterComponent.vue

Create a new file RegisterComponent.vue in the src/components directory:

<template>
  <div class="container mt-5">
    <div class="row justify-content-center">
      <div class="col-md-6">
        <div class="card">
          <div class="card-header">Registration</div>
          <div class="card-body">
            <form @submit.prevent="registerUser">
              <div class="form-group">
                <label>First Name</label>
                <input v-model="user.firstName" class="form-control" type="text" placeholder="Enter first name" />
              </div>
              <div class="form-group">
                <label>Last Name</label>
                <input v-model="user.lastName" class="form-control" type="text" placeholder="Enter last name" />
              </div>
              <div class="form-group">
                <label>Email</label>
                <input v-model="user.email" class="form-control" type="email" placeholder="Enter email address" />
              </div>
              <div class="form-group">
                <label>Password</label>
                <input v-model="user.password" class="form-control" type="password" placeholder="Enter password" />
              </div>
              <button type="submit" class="btn btn-primary">Register</button>
            </form>
            <div class="mt-3">
              <span>Already registered? <router-link to="/login">Login here</router-link></span>
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>
</template>

<script>
import AuthService from '../AuthService';

export default {
  data() {
    return {
      user: {
        firstName: '',
        lastName: '',
        email: '',
        password: ''
      }
    };
  },
  methods: {
    registerUser() {
      AuthService.register(this.user).then(response => {
        console.log(response.data);
      });
    }
  }
};
</script>

2.3.3 Create LoginComponent.vue

Create a new file LoginComponent.vue in the src/components directory:

<template>
  <div class="container mt-5">
    <div class="row justify-content-center">
      <div class="col-md-6">
        <div class="card">
          <div class="card-header">Login Form</div>
          <div class="card-body">
            <form @submit.prevent="loginUser">
              <div class="form-group">
                <label>Email</label>
                <input v-model="user.email" class="form-control" type="email" placeholder="Email" />
              </div>
              <div class="form-group">
                <label>Password</label>
                <input v-model="user.password" class="form-control" type="password" placeholder="Password" />
              </div>
              <button type="submit" class="btn btn-primary">Login</button>
            </form>
            <div class="mt-3">
              <span>Not registered? <router-link to="/register">Register/SignUp Here</router-link></span>
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>
</template>

<script>
import AuthService from '../AuthService';

export default {
  data() {
    return {
      user: {
        email: '',
        password: ''
      }
    };
  },
  methods: {
    loginUser() {
      AuthService.login(this.user).then(response => {
        console.log(response.data);
      });
    }
  }
};
</script>

2.3.4 Create App.vue

Modify the App.vue file to include routing for the components:

<template>
  <div id="app">
    <nav class="navbar navbar-expand-lg navbar-light bg-light">
      <a class="navbar-brand" href="#">JWT Authentication System</a>
    </nav>
    <router-view></router-view>
  </div>
</template>

<script>
export default {
  name: 'App'
};
</script>

<style>
nav {
  margin-bottom: 20px;
}
</style>

2.3.5 Update main.js

Ensure the main.js file is set

up correctly:

import { createApp } from 'vue';
import App from './App.vue';
import { createRouter, createWebHistory } from 'vue-router';
import RegisterComponent from './components/RegisterComponent.vue';
import LoginComponent from './components/LoginComponent.vue';
import 'bootstrap/dist/css/bootstrap.min.css';

const routes = [
  { path: '/', component: RegisterComponent },
  { path: '/register', component: RegisterComponent },
  { path: '/login', component: LoginComponent }
];

const router = createRouter({
  history: createWebHistory(),
  routes
});

const app = createApp(App);
app.use(router);
app.mount('#app');

Step 3: Running the Application

3.1 Run the Spring Boot Application

Open the JwtAuthenticationApplication class in the src/main/java/com/example/jwtauthentication directory.
Click the green Run button in your IDE or use the terminal to run the application:
```
./mvnw spring-boot:run
```

3.2 Run the Vue.js Application

Open a terminal and navigate to the vue-frontend directory.
Start the Vue application:
```
npm run serve
```
Open your web browser and navigate to http://localhost:8080.

You should now be able to register and log in users using the Vue.js frontend and Spring Boot backend. The backend will issue a JWT token upon successful login, which can be used to access secured endpoints.

Conclusion

In this tutorial, we created a full-stack application using Spring Boot for the backend and Vue.js for the frontend. We implemented JWT authentication and handled the necessary configurations to connect the two parts of the application. This setup provides a solid foundation for developing more secure full-stack applications.

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Spring Boot Vue.js JWT Authentication Example