在Java中处理JWT（Json Web Token）在页面每次进行操作时都自动刷新过期时间的操作实例

在Java中处理JWT自动刷新过期时间通常涉及到两个关键步骤：首先，你需要确保你的JWT包含了一个刷新令牌（Refresh Token），这个令牌可以在原JWT过期时用于请求新的访问令牌；其次，你需要实现一个服务或者API，该服务能够接受刷新令牌并返回一个新的有效JWT。

以下是一个简单的例子，假设你使用Spring Security和JJWT库：

1. 配置RefreshTokenProvider:

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;

public class JwtTokenProvider {
    private static final String REFRESH_TOKEN_SECRET = "your-refresh-token-secret";
    private static final long REFRESH_TOKEN_EXPIRATION_MINUTES = 60; // Refresh token expires in an hour

    public String createAccessToken(User user) {
        // Generate access token and add claims
        return Jwts.builder()
                .setSubject(user.getUsername())
                .signWith(SignatureAlgorithm.HS512, REFRESH_TOKEN_SECRET)
                .build().compact();
    }

    public String refreshToken(String refreshToken) {
        Claims claims = Jwts.parser().setSigningKey(REFRESH_TOKEN_SECRET).parseClaimsJws(refreshToken).getBody();
        // Validate refresh token and check if it's still valid
        if (claims != null && isTokenValid(claims)) {
            // Create a new access token with the same user details but refreshed expiration
            User userFromRefresh = getUserDetails(claims);
            return createAccessToken(userFromRefresh);
        }
        throw new IllegalArgumentException("Invalid refresh token");
    }

    private boolean isTokenValid(Claims claims) {
        // Implement your own logic to check if the token hasn't expired
    }

    private User getUserDetails(Claims claims) {
        // Extract user data from JWT claims
    }
}

2. 使用RefreshTokenFilter:

import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.web.filter.OncePerRequestFilter;

public class JwtRefreshTokenFilter extends OncePerRequestFilter {
    @Autowired
    private JwtTokenProvider jwtTokenProvider;

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

        // Check if the header exists
        if (authorizationHeader != null && authorizationHeader.startsWith("Bearer ")) {
            try {
                String accessToken = authorizationHeader.substring("Bearer ".length());
                String refreshToken = getRefreshTokenFromCacheOrDatabase(accessToken); // Retrieve from cache or database

                if (refreshToken != null) {
                    String refreshedAccessToken = jwtTokenProvider.refreshToken(refreshToken);
                    SecurityContextHolder.getContext().setAuthentication(new UsernamePasswordAuthenticationToken(
                            "user", "", jwtTokenProvider.getUserDetails(refreshedAccessToken)));
                } else {
                    throw new UnauthorizedException("Refresh token not found");
                }
            } catch (IllegalArgumentException e) {
                throw new UnauthorizedException(e.getMessage());
            }
        }

        chain.doFilter(request, response);
    }

    // Add methods to retrieve refresh tokens from cache or database
}

在这个例子中，当你尝试访问需要授权的资源时，`JwtRefreshTokenFilter`会检查`Authorization`头是否包含有效的JWT，并在必要时更新它。请注意这只是一个基础示例，实际应用中需要考虑更多边缘情况和安全性措施。