后端springboot中的jwt验证

<dependency>
    <groupId>io.jsonwebtoken</groupId>
    <artifactId>jjwt</artifactId>
    <version>0.9.1</version>
</dependency>

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import org.springframework.security.core.userdetails.UserDetails;

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

public class JwtUtil {

    private static final String SECRET_KEY = "yourSecretKey";

    public String generateToken(UserDetails userDetails) {
        Map<String, Object> claims = new HashMap<>();
        return createToken(claims, userDetails.getUsername());
    }

    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() + 1000 * 60 * 60 * 10)) // 10小时过期
                .signWith(SignatureAlgorithm.HS256, SECRET_KEY)
                .compact();
    }

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

    private String extractUsername(String token) {
        return Jwts.parser().setSigningKey(SECRET_KEY).parseClaimsJws(token).getBody().getSubject();
    }

    private Boolean isTokenExpired(String token) {
        return Jwts.parser().setSigningKey(SECRET => 'yourSecretKey').parseClaimsJws(token).getBody().getExpiration().before(new Date());
    }
}

@RestController
@RequestMapping("/api")
public class UserController {

    @Autowired
    private JwtUtil jwtUtil;

    @Autowired
    private AuthenticationManager authenticationManager;

    @PostMapping("/login")
    public ResponseEntity<?> login(@RequestBody AuthenticationRequest authenticationRequest) throws Exception {
        Authentication authentication = authenticationManager.authenticate(
                new UsernamePasswordAuthenticationToken(authenticationRequest.getUsername(), authenticationRequest.getPassword())
        );

        SecurityContextHolder.getContext().setAuthentication(authentication);
        String jwt = jwtUtil.generateToken((UserDetails) authentication.getPrincipal());

        return ResponseEntity.ok(new AuthenticationResponse(jwt));
    }

    @GetMapping("/user")
    public ResponseEntity<?> getCurrentUser(@RequestHeader("Authorization") String token) {
        if (token != null && token.startsWith("Bearer ")) {
            String jwtToken = token.substring(7);
            if (jwtUtil.validateToken(jwtToken, getCurrentAuthenticatedUser())) {
                String username = jwtUtil.extractUsername(jwtToken);
                // 返回用户信息
                return ResponseEntity.ok(new UserResponse(username));
            }
        }
        return ResponseEntity.status(HttpStatus.UNAUTHORIZED).build();
    }

    private UserDetails getCurrentAuthenticatedUser() {
        // 获取当前认证的用户详情
    }
}