Agent Skills: Spring Boot JWT Security

Spring Boot JWT Security

JWT authentication and authorization patterns for Spring Boot 3.5.x using Spring Security 6.x and JJWT. Covers token generation, validation, refresh strategies, RBAC/ABAC, and OAuth2 integration.

Overview

This skill provides implementation patterns for stateless JWT authentication in Spring Boot applications. It covers the complete authentication flow including token generation with JJWT 0.12.6, Bearer/cookie-based authentication, refresh token rotation, and method-level authorization with @PreAuthorize expressions.

Key capabilities:

• Access and refresh token generation with configurable expiration
• Bearer token and HttpOnly cookie authentication strategies
• Integration with Spring Data JPA and OAuth2 providers
• RBAC with role/permission-based @PreAuthorize rules
• Token revocation and blacklisting for logout/rotation

When to Use

Activate when user requests involve:

• "Implement JWT authentication", "secure REST API with tokens"
• "Spring Security 6.x configuration", "SecurityFilterChain setup"
• "Role-based access control", "RBAC", `@PreAuthorize`
• "Refresh token", "token rotation", "token revocation"
• "OAuth2 integration", "social login", "Google/GitHub auth"
• "Stateless authentication", "SPA backend security"
• "JWT filter", "OncePerRequestFilter", "Bearer token"
• "Cookie-based JWT", "HttpOnly cookie"
• "Permission-based access control", "custom PermissionEvaluator"

Quick Reference

Dependencies (JJWT 0.12.6)

| Artifact | Scope | |----------|-------| | spring-boot-starter-security | compile | | spring-boot-starter-oauth2-resource-server | compile | | io.jsonwebtoken:jjwt-api:0.12.6 | compile | | io.jsonwebtoken:jjwt-impl:0.12.6 | runtime | | io.jsonwebtoken:jjwt-jackson:0.12.6 | runtime | | spring-security-test | test |

See references/jwt-quick-reference.md for Maven and Gradle snippets.

Key Configuration Properties

| Property | Example Value | Notes | |----------|--------------|-------| | jwt.secret | ${JWT_SECRET} | Min 256 bits, never hardcode | | jwt.access-token-expiration | 900000 | 15 min in milliseconds | | jwt.refresh-token-expiration | 604800000 | 7 days in milliseconds | | jwt.issuer | my-app | Validated on every token | | jwt.cookie-name | jwt-token | For cookie-based auth | | jwt.cookie-http-only | true | Always true in production | | jwt.cookie-secure | true | Always true with HTTPS |

Authorization Annotations

| Annotation | Example | |-----------|---------| | @PreAuthorize("hasRole('ADMIN')") | Role check | | @PreAuthorize("hasAuthority('USER_READ')") | Permission check | | @PreAuthorize("hasPermission(#id, 'Doc', 'READ')") | Domain object check | | @PreAuthorize("@myService.canAccess(#id)") | Spring bean check |

Instructions

Step 1 — Add Dependencies

Include spring-boot-starter-security, spring-boot-starter-oauth2-resource-server, and the three JJWT artifacts in your build file. See references/jwt-quick-reference.md for exact Maven/Gradle snippets.

Step 2 — Configure application.yml

jwt:
  secret: ${JWT_SECRET:change-me-min-32-chars-in-production}
  access-token-expiration: 900000
  refresh-token-expiration: 604800000
  issuer: my-app
  cookie-name: jwt-token
  cookie-http-only: true
  cookie-secure: false   # true in production

See references/jwt-complete-configuration.md for the full properties reference.

Step 3 — Implement JwtService

Core operations: generate access token, generate refresh token, extract username, validate token.

@Service
public class JwtService {

    public String generateAccessToken(UserDetails userDetails) {
        return Jwts.builder()
            .subject(userDetails.getUsername())
            .issuer(issuer)
            .issuedAt(new Date())
            .expiration(new Date(System.currentTimeMillis() + accessTokenExpiration))
            .claim("authorities", getAuthorities(userDetails))
            .signWith(getSigningKey())
            .compact();
    }

    public boolean isTokenValid(String token, UserDetails userDetails) {
        try {
            String username = extractUsername(token);
            return username.equals(userDetails.getUsername()) && !isTokenExpired(token);
        } catch (JwtException e) {
            return false;
        }
    }
}

See references/jwt-complete-configuration.md for the complete JwtService including key management and claim extraction.

Step 4 — Create JwtAuthenticationFilter

Extend OncePerRequestFilter to extract a JWT from the Authorization: Bearer header (or HttpOnly cookie), validate it, and set the SecurityContext.

@Component
public class JwtAuthenticationFilter extends OncePerRequestFilter {

    @Override
    protected void doFilterInternal(HttpServletRequest request,
            HttpServletResponse response, FilterChain chain)
            throws ServletException, IOException {
        String authHeader = request.getHeader("Authorization");
        if (authHeader == null || !authHeader.startsWith("Bearer ")) {
            chain.doFilter(request, response);
            return;
        }
        String jwt = authHeader.substring(7);
        String username = jwtService.extractUsername(jwt);
        if (username != null && SecurityContextHolder.getContext().getAuthentication() == null) {
            UserDetails userDetails = userDetailsService.loadUserByUsername(username);
            if (jwtService.isTokenValid(jwt, userDetails)) {
                UsernamePasswordAuthenticationToken authToken =
                    new UsernamePasswordAuthenticationToken(
                        userDetails, null, userDetails.getAuthorities());
                authToken.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));
                SecurityContextHolder.getContext().setAuthentication(authToken);
            }
        }
        chain.doFilter(request, response);
    }
}

See references/configuration.md for the cookie-based variant.

Step 5 — Configure SecurityFilterChain

@Configuration
@EnableWebSecurity
@EnableMethodSecurity
public class SecurityConfig {

    @Bean
    public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
        return http
            .csrf(AbstractHttpConfigurer::disable)
            .sessionManagement(s -> s.sessionCreationPolicy(SessionCreationPolicy.STATELESS))
            .authorizeHttpRequests(auth -> auth
                .requestMatchers("/api/auth/**", "/swagger-ui/**").permitAll()
                .anyRequest().authenticated()
            )
            .authenticationProvider(authenticationProvider)
            .addFilterBefore(jwtAuthFilter, UsernamePasswordAuthenticationFilter.class)
            .build();
    }
}

See references/jwt-complete-configuration.md for CORS, logout handler, and OAuth2 login integration.

Step 6 — Create Authentication Endpoints

Expose /register, /authenticate, /refresh, and /logout via @RestController. Return accessToken + refreshToken in the response body (and optionally set an HttpOnly cookie).

See references/examples.md for the complete AuthenticationController and AuthenticationService.

Step 7 — Implement Refresh Token Strategy

Store refresh tokens in the database with user_id, expiry_date, revoked, and expired columns. On /refresh, verify the stored token, revoke it, and issue a new pair (token rotation).

See references/token-management.md for RefreshToken entity, rotation logic, and Redis-based blacklisting.

Step 8 — Add Authorization Rules

Use @EnableMethodSecurity and @PreAuthorize annotations for fine-grained control:

@PreAuthorize("hasRole('ADMIN')")
public Page<UserResponse> getAllUsers(Pageable pageable) { ... }

@PreAuthorize("hasPermission(#documentId, 'Document', 'READ')")
public Document getDocument(Long documentId) { ... }

See references/authorization-patterns.md for RBAC entity model, PermissionEvaluator, and ABAC patterns.

Step 9 — Write Security Tests

@SpringBootTest
@AutoConfigureMockMvc
class AuthControllerTest {

    @Test
    void shouldDenyAccessWithoutToken() throws Exception {
        mockMvc.perform(get("/api/orders"))
            .andExpect(status().isUnauthorized());
    }

    @Test
    @WithMockUser(roles = "ADMIN")
    void shouldAllowAdminAccess() throws Exception {
        mockMvc.perform(get("/api/admin/users"))
            .andExpect(status().isOk());
    }
}

See references/testing.md and references/jwt-testing-guide.md for full test suites, Testcontainers setup, and a security test checklist.

Best Practices

Token Security

• Use minimum 256-bit secret keys — load from environment variables, never hardcode
• Set short access token lifetimes (15 min); use refresh tokens for longer sessions
• Implement token rotation: revoke old refresh token when issuing a new one
• Use jti (JWT ID) claim for blacklisting on logout

Cookie vs Bearer Header

• Prefer HttpOnly cookies for browser clients (XSS-safe)
• Use Authorization: Bearer header for mobile/API clients
• Set Secure, SameSite=Lax or Strict on cookies in production

Spring Security 6.x

• Use SecurityFilterChain bean — never extend WebSecurityConfigurerAdapter
• Disable CSRF only for stateless APIs; keep it enabled for session-based flows
• Use @EnableMethodSecurity instead of deprecated @EnableGlobalMethodSecurity
• Validate iss and aud claims; reject tokens from untrusted issuers

Performance

• Cache UserDetails with @Cacheable to avoid DB lookup on every request
• Cache signing key derivation (avoid re-computing HMAC key per request)
• Use Redis for refresh token storage at scale

What NOT to Do

• Do not store sensitive data (passwords, PII) in JWT claims — claims are only signed, not encrypted
• Do not issue tokens with infinite lifetime
• Do not accept tokens without validating signature and expiration
• Do not share signing keys across environments

Examples

Basic Authentication Flow

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

    private final AuthService authService;

    @PostMapping("/authenticate")
    public ResponseEntity<AuthResponse> authenticate(
            @RequestBody LoginRequest request) {
        return ResponseEntity.ok(authService.authenticate(request));
    }

    @PostMapping("/refresh")
    public ResponseEntity<AuthResponse> refresh(@RequestBody RefreshRequest request) {
        return ResponseEntity.ok(authService.refreshToken(request.refreshToken()));
    }

    @PostMapping("/logout")
    public ResponseEntity<Void> logout() {
        authService.logout();
        return ResponseEntity.ok().build();
    }
}

JWT Authorization on Controller Method

@RestController
@RequestMapping("/api/admin")
@PreAuthorize("hasRole('ADMIN')")
public class AdminController {

    @GetMapping("/users")
    public ResponseEntity<List<UserResponse>> getAllUsers() {
        return ResponseEntity.ok(adminService.getAllUsers());
    }
}

See references/examples.md for complete entity models and service implementations.

References

| File | Content | |------|---------| | references/jwt-quick-reference.md | Dependencies, minimal service, common patterns | | references/jwt-complete-configuration.md | Full config: properties, SecurityFilterChain, JwtService, OAuth2 RS | | references/configuration.md | JWT config beans, CORS, CSRF, error handling, session options | | references/examples.md | Complete application setup: controllers, services, entities | | references/authorization-patterns.md | RBAC/ABAC entity model, PermissionEvaluator, SpEL expressions | | references/token-management.md | Refresh token entity, rotation, blacklisting with Redis | | references/testing.md | Unit and MockMvc tests, test utilities | | references/jwt-testing-guide.md | Testcontainers, load testing, security test checklist | | references/security-hardening.md | Security headers, HSTS, rate limiting, audit logging | | references/performance-optimization.md | Caffeine cache config, async validation, connection pooling | | references/oauth2-integration.md | Google/GitHub OAuth2 login, OAuth2UserService | | references/microservices-security.md | Inter-service JWT propagation, resource server config | | references/migration-spring-security-6x.md | Migration from Spring Security 5.x | | references/troubleshooting.md | Common errors, debugging tips |

Constraints and Warnings

Security Constraints

• JWT tokens are signed but not encrypted — do not include sensitive data in claims
• Always validate exp, iss, and aud claims before trusting the token
• Signing keys must be at least 256 bits; never use weak keys in production
• Load secrets from environment variables or secure vaults, never from config files
• SameSite cookie attribute is essential for CSRF protection in cookie-based flows

Spring Security 6.x Constraints

• WebSecurityConfigurerAdapter is removed — use SecurityFilterChain beans only
• @EnableGlobalMethodSecurity is deprecated — use @EnableMethodSecurity
• Lambda DSL is required for HttpSecurity configuration (no method chaining)
• WebSecurityConfigurerAdapter.order() replaced by @Order on @Configuration classes

Token Constraints

• Access tokens should expire in 5-15 minutes for security
• Refresh tokens should be stored server-side (DB or Redis), never in localStorage
• Implement token blacklisting for immediate revocation on logout
• jti claim is required for token blacklisting to work correctly

Related Skills

• spring-boot-dependency-injection — Constructor injection patterns used throughout
• spring-boot-rest-api-standards — REST API security patterns and error handling
• unit-test-security-authorization — Testing Spring Security configurations
• spring-data-jpa — User entity and repository patterns
• spring-boot-actuator — Security monitoring and health endpoints