Secure your Restful WebServices using JWT | Spring Boot
Tags: springboot, java, rest, jwt
Published: 2021-03-21 05:37:05

JWT(JSON Web Token) is the most popular way of securing your Restful Web Services. If you want to learn more about JWT, please refer the following website -

[JWT Reference] (https://jwt.io/)

This article is intended towards a working example of how JWT can be implemented using Spring Boot, Spring Security and Relational Database(MySQL in this example).

* Create a new Spring Boot project and add the following dependencies -

```
<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-security</artifactId>
		</dependency>
		<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>javax.xml.bind</groupId>
			<artifactId>jaxb-api</artifactId>
		</dependency>
		<dependency>
			<groupId>io.jsonwebtoken</groupId>
			<artifactId>jjwt</artifactId>
			<version>0.9.1</version>
		</dependency>
		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<optional>true</optional>
		</dependency>
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<scope>runtime</scope>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
			<exclusions>
				<exclusion>
					<groupId>org.junit.vintage</groupId>
					<artifactId>junit-vintage-engine</artifactId>
				</exclusion>
			</exclusions>
		</dependency>
		<dependency>
			<groupId>org.springframework.security</groupId>
			<artifactId>spring-security-test</artifactId>
			<scope>test</scope>
		</dependency>
```

* Add the following properties in application.properties that resides in src/main/resources -

```
server.port=9091
jwtdemo.secretKey=jWtSpRiNgBoOtExAmPlE

spring.datasource.url = jdbc:mysql://localhost:3306/<Database Name>?useSSL=false
spring.datasource.username = <DB User Name>
spring.datasource.password = <DB Password>


## Hibernate Properties
# The SQL dialect makes Hibernate generate better SQL for the chosen database
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5InnoDBDialect

# Hibernate ddl auto (create, create-drop, validate, update)
spring.jpa.hibernate.ddl-auto = update
```
* Add the following Configuration class to read the values from properties file - 

```
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;

@Configuration
@ConfigurationProperties(prefix = "jwtdemo")
@Data
@AllArgsConstructor
@NoArgsConstructor
public class ConfigProperties {
    private String secretKey;
}
```
* Add the following Security Configuration.

```
import com.springboot.jwt.filter.JWTFilter;
import com.springboot.jwt.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.builders.AuthenticationManagerBuilder;
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.http.SessionCreationPolicy;
import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;

@Configuration
@EnableWebSecurity
public class SecurityConfiguration extends WebSecurityConfigurerAdapter {

    @Autowired
    private UserService userService;

    @Autowired
    private JWTFilter jwtFilter;

    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.userDetailsService(userService);
    }

    @Override
    @Bean
    public AuthenticationManager authenticationManagerBean() throws Exception {
        return super.authenticationManagerBean();
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.csrf()
                .disable()
                .authorizeRequests()
                .antMatchers("/authenticate", "/add-user")
                .permitAll()
                .anyRequest()
                .authenticated()
                .and()
                .sessionManagement()
                .sessionCreationPolicy(SessionCreationPolicy.STATELESS);

        http.addFilterBefore(jwtFilter, UsernamePasswordAuthenticationFilter.class);
    }
```
* Add the following Entity class which corresponding to the database table -

```
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import javax.persistence.*;

@Entity
@Table(name = "userdetails")
@Data
@NoArgsConstructor
@AllArgsConstructor
public class UserEntity {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;

    @Column(name = "first_name")
    private String firstName;

    @Column(name = "last_name")
    private String lastName;

    @Column(name = "email")
    private String email;

    @Column(name = "user_name")
    private String userName;

    @Column(name = "password")
    private String password;
}

``` 

* Add the database repository interface

```
import com.springboot.jwt.entity.UserEntity;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface UserRepository extends JpaRepository<UserEntity, Long> {
    UserEntity findByUserName(String userName);
}
```

* Add the following JWT Utility class -

```
import com.springboot.jwt.config.ConfigProperties;
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Component;

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

@Component
public class JWTUtility implements Serializable {

    private static final long serialVersionUID = 1L;

    public static final long JWT_TOKEN_VALIDITY = 5 * 60 * 60;

    @Autowired
    private ConfigProperties configProperties;

    //retrieve username from jwt token
    public String getUsernameFromToken(String token) {
        return getClaimFromToken(token, Claims::getSubject);
    }

    //retrieve expiration date from jwt token
    public Date getExpirationDateFromToken(String token) {
        return getClaimFromToken(token, Claims::getExpiration);
    }


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


    //for retrieving any information from token we will need the secret key
    private Claims getAllClaimsFromToken(String token) {
        return Jwts.parser().setSigningKey(configProperties.getSecretKey()).parseClaimsJws(token).getBody();
    }


    //check if the token has expired
    private Boolean isTokenExpired(String token) {
        final Date expiration = getExpirationDateFromToken(token);
        return expiration.before(new Date());
    }


    //generate token for user
    public String generateToken(UserDetails userDetails) {
        Map<String, Object> claims = new HashMap<>();
        return doGenerateToken(claims, userDetails.getUsername());
    }


    //while creating the token -
    //1. Define  claims of the token, like Issuer, Expiration, Subject, and the ID
    //2. Sign the JWT using the HS512 algorithm and secret key.
    private String doGenerateToken(Map<String, Object> claims, String subject) {
        return Jwts.builder().setClaims(claims).setSubject(subject).setIssuedAt(new Date(System.currentTimeMillis()))
                .setExpiration(new Date(System.currentTimeMillis() + JWT_TOKEN_VALIDITY * 1000))
                .signWith(SignatureAlgorithm.HS512, configProperties.getSecretKey()).compact();
    }


    //validate token
    public Boolean validateToken(String token, UserDetails userDetails) {
        final String username = getUsernameFromToken(token);
        return (username.equals(userDetails.getUsername()) && !isTokenExpired(token));
    }
```

* Add the following model objects for sending and receiving JWT Request and Response data simultaneously.

```
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class JWTRequest {

    private String userName;
    private String password;
}
```
```
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class JWTResponse {

    private String jwtToken;
}
```
* Add the JWT Request Filter for performing the authentication.

```
import com.springboot.jwt.service.UserService;
import com.springboot.jwt.utility.JWTUtility;
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 JWTFilter extends OncePerRequestFilter {

    @Autowired
    private JWTUtility jwtUtility;

    @Autowired
    private UserService userService;

    @Override
    protected void doFilterInternal(HttpServletRequest httpServletRequest,
                                    HttpServletResponse httpServletResponse,
                                    FilterChain filterChain) throws ServletException, IOException {

        String authorization = httpServletRequest.getHeader("Authorization");
        String token = null;
        String userName = null;

        if(null != authorization && authorization.startsWith("Bearer ")) {
            token = authorization.substring(7);
            userName = jwtUtility.getUsernameFromToken(token);
        }

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

            if(jwtUtility.validateToken(token,userDetails)) {
                UsernamePasswordAuthenticationToken usernamePasswordAuthenticationToken
                        = new UsernamePasswordAuthenticationToken(userDetails, null, userDetails.getAuthorities());

                usernamePasswordAuthenticationToken.setDetails(
                        new WebAuthenticationDetailsSource().buildDetails(httpServletRequest));

                SecurityContextHolder.getContext().setAuthentication(usernamePasswordAuthenticationToken);
            }

        }
        filterChain.doFilter(httpServletRequest, httpServletResponse);
    }
}
```

* Add the Service class -
```
import com.springboot.jwt.entity.UserEntity;
import com.springboot.jwt.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.stereotype.Service;

import java.util.ArrayList;

@Service
public class UserService implements UserDetailsService {

    @Autowired
    private UserRepository userRepository;

    @Override
    public UserDetails loadUserByUsername(String s) throws UsernameNotFoundException {
        UserEntity userEntity = userRepository.findByUserName(s);
        return new User(userEntity.getUserName(), userEntity.getPassword(), new ArrayList<>());
    }
}
```
* Add the Controller class with three endpoints- /add-user endpoint is used for adding user to database, /authenticate is used for JWT Authentication, /restricted-access-rest-endpoint is a restricted endpoint which can be used post successful JWT authentication -
```
import com.springboot.jwt.entity.UserEntity;
import com.springboot.jwt.model.JWTRequest;
import com.springboot.jwt.model.JWTResponse;
import com.springboot.jwt.repository.UserRepository;
import com.springboot.jwt.service.UserService;
import com.springboot.jwt.utility.JWTUtility;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.authentication.BadCredentialsException;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
@Slf4j
public class UserController {

    @Autowired
    private JWTUtility jwtUtility;

    @Autowired
    private AuthenticationManager authenticationManager;

    @Autowired
    private UserService userService;

    @Autowired
    private UserRepository userRepository;

    @Autowired
    private PasswordEncoder passwordEncoder;

    @PostMapping("/add-user")
    public UserEntity createUser(@RequestBody UserEntity userEntity) {
        log.info("Saving the new user with user name : " + userEntity.getUserName());
        userEntity.setPassword(passwordEncoder.encode(userEntity.getPassword()));
        return userRepository.save(userEntity);
    }

    @GetMapping("/restricted-access-rest-endpoint")
    public String restrictedAccessEndpoint() {
        return "Welcome to the demo of JWT with Spring Boot!!!!";
    }

    @PostMapping("/authenticate")
    public JWTResponse authenticate(@RequestBody JWTRequest jwtRequest) throws Exception {
        try {
            authenticationManager.authenticate
                    (new UsernamePasswordAuthenticationToken(jwtRequest.getUserName(), jwtRequest.getPassword()));

        } catch (BadCredentialsException e) {
            throw new Exception("INVALID_CREDENTIALS", e);
        }
        final UserDetails userDetails = userService.loadUserByUsername(jwtRequest.getUserName());
        final String token = jwtUtility.generateToken(userDetails);
        return new JWTResponse(token);
    }
}
```
* The entire source code is available in the following link - 
[JWTCodebase](https://github.com/pradz13/JWTDemoSpringBoot)