Spring Boot 的 JWT 身份验证简化指南

2025-06-04

Spring Boot 的 JWT 身份验证简化指南

介绍：

在当今的数字环境中，保护应用程序安全至关重要。JWT（JSON Web Token）身份验证是一种可靠的方法。它提供了一种安全的用户身份验证方式。在本指南中，我们将使用一种简化但有效的方法，在 Spring Boot 应用中逐步实现 JWT 身份验证。我们将涵盖控制器、服务、配置和存储库，确保您能够充分增强应用程序的安全性。

🚀步骤 1：设置您的 Spring Boot 项目
首先创建一个新的 Spring Boot 项目或利用现有项目。使用 Spring Initializr 可以加快此过程，它会设置必要的依赖项，例如 Spring Web、Spring Security 和 Spring Data JPA。

<!-- Include necessary dependencies in your pom.xml file -->
<dependencies>
    <!-- Spring Web for creating web APIs -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!-- Spring Security for robust authentication and authorization -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-security</artifactId>
    </dependency>
    <!-- Spring Data JPA for streamlined database interactions -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
   <dependency>
    <groupId>io.jsonwebtoken</groupId>
    <artifactId>jjwt</artifactId>
    <version>0.9.1</version>
  </dependency>
    <!-- Other dependencies... -->
</dependencies>
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📦步骤 2：创建用户实体和存储库。
设计一个User包含id、username和 等属性的类password。开发一个UserRepository界面以方便顺畅地管理用户数据。

@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String username;
    private String password;
    // Getters, setters...
}

public interface UserRepository extends JpaRepository<User, Long> {
    User findByUsername(String username);
}
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🔒步骤 3：配置 Spring Security
创建一个SecurityConfig扩展类WebSecurityConfigurerAdapter。重写configure(HttpSecurity http)以建立安全规则并管理 JWT 身份验证。

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
    @Autowired
    private UserDetailsService userDetailsService;

    @Autowired
    private JwtUtil jwtUtil;

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.csrf().disable()
            .authorizeRequests()
                .antMatchers("/api/auth/**").permitAll()
                .anyRequest().authenticated()
            .and()
            .addFilter(new JwtAuthenticationFilter(authenticationManager(), jwtUtil))
            .addFilter(new JwtAuthorizationFilter(authenticationManager(), jwtUtil, userDetailsService));
    }

    // Additional configurations...
}
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👤步骤 4：实现 UserService
开发一个UserService接口，其中包含通过用户名加载用户和保存新用户的方法。实现UserDetailsService从数据库检索用户详细信息的功能。

@Service
public interface UserService extends UserDetailsService {
    UserDetails loadUserByUsername(String username);
    void saveUser(User user);
}

@Service
public class UserServiceImpl implements UserService {
    @Autowired
    private UserRepository userRepository;

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        User user = userRepository.findByUsername(username);
        if (user == null) {
            throw new UsernameNotFoundException("User not found: " + username);
        }
        return new org.springframework.security.core.userdetails.User(
            user.getUsername(),
            user.getPassword(),
            new ArrayList<>()
        );
    }

    @Override
    public void saveUser(User user) {
        userRepository.save(user);
    }
}
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🔐步骤 5：生成和验证 JWT 令牌
创建一个JwtUtil类来生成和验证 JWT 令牌。

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
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 {
    private final String SECRET = "your-secret-key"; // Replace with a secure secret key
    private final long EXPIRATION_TIME = 900_000; // 15 minutes

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

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

    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_TIME))
                .signWith(SignatureAlgorithm.HS256, SECRET)
                .compact();
    }

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

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

    // Additional utility methods...
}
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🔑第 6 步：身份验证控制器
设计一个AuthController类来处理用户注册和身份验证。

@RestController
@RequestMapping("/api/auth")
public class AuthController {
    @Autowired
    private AuthenticationManager authenticationManager;

    @Autowired
    private UserService userService;

    @Autowired
    private JwtUtil jwtUtil;

    @PostMapping("/register")
    public ResponseEntity<String> registerUser(@RequestBody User user) {
        userService.saveUser(user);
        return ResponseEntity.ok("User registered successfully!");
    }

    @PostMapping("/login")
    public ResponseEntity<String> loginUser(@RequestBody AuthenticationRequest request) {
        try {
            authenticationManager.authenticate(
                new UsernamePasswordAuthenticationToken(request.getUsername(), request.getPassword())
            );
        } catch (BadCredentialsException e) {
            return ResponseEntity.status(HttpStatus.UNAUTHORIZED).body("Invalid username or password");
        }

        UserDetails userDetails = userService.loadUserByUsername(request.getUsername());
        String token = jwtUtil.generateToken(userDetails);

        return ResponseEntity.ok(token);
    }
}
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🔍步骤 7：实现 JwtAuthenticationFilter
创建一个JwtAuthenticationFilter类来处理每个请求的 JWT 身份验证和授权。

@Component
public class JwtAuthenticationFilter extends OncePerRequestFilter {
    @Autowired
    private UserDetailsService userDetailsService;

    @Autowired
    private JwtUtil jwtTokenUtil;

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

        String username = null;
        String jwtToken = null;

        if (authorizationHeader != null && authorizationHeader.startsWith("Bearer ")) {
            jwtToken = authorizationHeader.substring(7);
            try {
                username = jwtTokenUtil.extractUsername(jwtToken);
            } catch (Exception e) {
                // Handle token extraction/validation errors
                System.out.println("Error extracting username from token: " + e.getMessage());
            }
        }

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

            if (jwtTokenUtil.validateToken(jwtToken, userDetails)) {
                UsernamePasswordAuthenticationToken authenticationToken = new UsernamePasswordAuthenticationToken(
                        userDetails, null, userDetails.getAuthorities());

                authenticationToken.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));

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

        filterChain.doFilter(request, response);
    }
}
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🌟结论：
您已成功在 Spring Boot 应用中实现 JWT 身份验证！🎉 您的应用现在拥有更高的安全性，可确保只有授权用户才能访问敏感资源。请记住，安全是一个持续的过程，因此请随时了解最佳实践，并持续增强应用的防御能力。祝您编码愉快，安全无虞！🔒🔐

文章来源：https://dev.to/abhi9720/a-compressive-guide-to-jwt-authentication-with-spring-boot-117p
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