JWT - nhnacademy-be10-WannaB/wannab-wiki GitHub Wiki

Header:  { "alg": "HS256", "typ": "JWT" }
Payload: { "userId": 123, "role": "admin" }

message = base64UrlEncode(Header) + "." + base64UrlEncode(Payload)
Signature = HMAC-SHA256(message, secret_key)

package com.example.jwt.demo_jwt;
import static java.security.KeyRep.Type.SECRET;
import io.jsonwebtoken.*;
import io.jsonwebtoken.security.Keys;
import java.nio.charset.StandardCharsets;
import java.security.Key;
import java.util.Date;
public class JwtUtil {
private static final String SECRET = "P3C+yJU3dv7iXM2umvApxy7NTkfm2BL6V3GBIPTbe/Q=";
private static final Key SECRET_KEY = Keys.hmacShaKeyFor(SECRET.getBytes(StandardCharsets.UTF_8));
public static String createAccessToken(String username) {
    return Jwts.builder()
            .setSubject(username)
            .setIssuedAt(new Date())
            .setExpiration(new Date(System.currentTimeMillis() + 15 * 60 * 1000)) // 15분
            .signWith(SignatureAlgorithm.HS256, SECRET_KEY)
            .compact();
}

public static String createRefreshToken(String username) {
    return Jwts.builder()
            .setSubject(username)
            .setIssuedAt(new Date())
            .setExpiration(new Date(System.currentTimeMillis() + 7 * 24 * 60 * 60 * 1000)) // 7일
            .claim("type", "refresh") // 추가 구분자 claim
            .signWith(SignatureAlgorithm.HS256, SECRET_KEY)
            .compact();
}

// 토큰 검증 및 파싱
public static String validateAndGetUsername(String token) {
    return Jwts.parser()
            .setSigningKey(SECRET_KEY)
            .parseClaimsJws(token)
            .getBody()
            .getSubject();
}

}

import jakarta.servlet.http.Cookie;
import jakarta.servlet.http.HttpServletResponse;
import org.springframework.web.bind.annotation.*;
@RestController
public class AuthController {
@PostMapping("/login")
public String login(@RequestParam String username,
                    @RequestParam String password,
                    HttpServletResponse response) {

    // 실제로는 username/password를 DB에서 검증해야 함
    if ("user".equals(username) && "1234".equals(password)) {
        String jwt = JwtUtil.generateToken(username);

        Cookie cookie = new Cookie("access_token", jwt);
        cookie.setHttpOnly(true);           // 자바스크립트에서 접근 불가
        cookie.setSecure(true);             // HTTPS 환경에서만 전송
        cookie.setPath("/");                // 전체 경로에서 사용 가능
        cookie.setMaxAge(60 * 60);          // 1시간 유효

        response.addCookie(cookie);

        return "로그인 성공";
    } else {
        return "아이디 또는 비밀번호 오류";
    }
}

}

@Configuration
public class WebConfig implements WebMvcConfigurer {
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")
                .allowedOrigins("<http://localhost:3000>") // 프론트 주소
                .allowedMethods("*")
                .allowCredentials(true); // -> 허용 해줘야함
    }
}

axios.post("<https://yourdomain.com/login>", {
  username: "user",
  password: "1234"
}, {
  withCredentials: true // -> 설정 
});

        <dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt-api</artifactId>
            <version>0.11.5</version>
        </dependency>
        <dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt-impl</artifactId>
            <version>0.11.5</version>
        </dependency>
        <dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt-jackson</artifactId>
            <version>0.11.5</version>
        </dependency>

byte[] keyBytes = new byte[byteLength];
new SecureRandom().nextBytes(keyBytes);
return Base64.getEncoder().encodeToString(32); // 32바이트 = 256비트
private static final String SECRET = "P3C+yJU3dv7iXM2umvApxy7NTkfm2BL6V3GBIPTbe/Q=";
private static final Key SECRET_KEY = Keys.hmacShaKeyFor(SECRET.getBytes(StandardCharsets.UTF_8));