{
  "alg": "HS256",
  "typ": "JWT"
}

{
  "sub": "1234567890",
  "name": "John Doe",
  "admin": true
}

<!--引入jwt-->
<dependency>
  <groupId>com.auth0</groupId>
  <artifactId>java-jwt</artifactId>
  <version>3.4.0</version>
</dependency>

@Test
void contextLoads() {
    HashMap<String, Object> map = new HashMap<>();
    Calendar instance=Calendar.getInstance();
    instance.add(Calendar.SECOND,200);
    //獲取token
    String token = JWT.create().withHeader(map)  //header，默認(rèn)，可以不寫
        .withClaim("userId", 23)
        .withClaim("username", "xpp") //palyload
        .withExpiresAt(instance.getTime())  //指定令牌的過期時間
        .sign(Algorithm.HMAC256("xpp@ll"));//簽名，指定秘鑰
    System.out.println(token);

}

@Test
public void test(){
    //創(chuàng)建驗證對象
    JWTVerifier jwtVerifier = JWT.require(Algorithm.HMAC256("xpp@ll")).build();
    //驗證token
    DecodedJWT verify = jwtVerifier.verify("eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJleHAiOjE2Mzc5MDM2OTksInVzZXJJZCI6MjMsInVzZXJuYW1lIjoieHBwIn0.dnWldEBILZpt7Upz762VcMm-uTU9HI5jK-AHk3XyX0s");
    //獲取存入palyload的信息
    Date expiresAt = verify.getExpiresAt();
    System.out.println(expiresAt);
    System.out.println(verify.getClaim("userId").asInt());
}

<!--引入jwt-->
<dependency>
  <groupId>com.auth0</groupId>
  <artifactId>java-jwt</artifactId>
  <version>3.4.0</version>
</dependency>

<!--引入mybatis-->
<dependency>
  <groupId>org.mybatis.spring.boot</groupId>
  <artifactId>mybatis-spring-boot-starter</artifactId>
  <version>2.1.3</version>
</dependency>

<!--引入lombok-->
<dependency>
  <groupId>org.projectlombok</groupId>
  <artifactId>lombok</artifactId>
  <version>1.18.12</version>
</dependency>

<!--引入druid-->
<dependency>
  <groupId>com.alibaba</groupId>
  <artifactId>druid</artifactId>
  <version>1.1.19</version>
</dependency>

<!--引入mysql-->
<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>5.1.38</version>
</dependency>

server.port=8989
spring.application.name=jwt

spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/jwt?characterEncoding=UTF-8
spring.datasource.username=root
spring.datasource.password=root

mybatis.type-aliases-package=com.baizhi.entity
mybatis.mapper-locations=classpath:com/baizhi/mapper/*.xml

logging.level.com.baizhi.dao=debug

DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主鍵',
  `name` varchar(80) DEFAULT NULL COMMENT '用戶名',
  `password` varchar(40) DEFAULT NULL COMMENT '用戶密碼',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;

@Data
@Accessors(chain=true)
public class User {
    private String id;
    private String name;
    private String password;
}

@Mapper
public interface UserDAO {
    User login(User user);
}

<mapper namespace="com.baizhi.dao.UserDAO">
    <!--這里就寫的簡單點了畢竟不是重點-->
    <select id="login" parameterType="User" resultType="User">
        select * from user where name=#{name} and password = #{password}
    </select>
</mapper>

public interface UserService {
    User login(User user);//登錄接口
}

@Service
@Transactional
public class UserServiceImpl implements UserService {
    @Autowired
    private UserDAO userDAO;
    @Override
    @Transactional(propagation = Propagation.SUPPORTS)
    public User login(User user) {
        User userDB = userDAO.login(user);
        if(userDB!=null){
            return userDB;
        }
        throw  new RuntimeException("登錄失敗~~");
    }
}

/**
 * @Auther: xppll
 * @Date: 2021/11/26 13:25
 */
public class JWTUtils {
    //秘鑰
    private static final String TOKEN = "xpp@ll";

    /**
     * 生成token(head.playload.sing)
     *
     * @param map 用戶傳過了的信息，例如id等
     * @return
     */
    public static String getToken(Map<String, String> map) {
        Calendar instance = Calendar.getInstance();
        //設(shè)置默認(rèn)7天過期
        instance.add(Calendar.DATE, 7);

        //創(chuàng)建jwt builder
        JWTCreator.Builder builder = JWT.create();
        //payload
        map.forEach((k, v) -> {
            builder.withClaim(k, v);
        });
        //指定令牌過期時間
        String token = builder.withExpiresAt(instance.getTime())
                //sign，傳入加密鹽
                .sign(Algorithm.HMAC256(TOKEN));
        return token;
    }

    /**
     * 驗證token合法性
     *
     * @param token
     */
    public static void verify(String token) {
        JWT.require(Algorithm.HMAC256(TOKEN)).build().verify(token);
    }

    /**
     * 獲取token信息方法
     *
     * @param token
     * @return
     */
    public static DecodedJWT getTokenInfo(String token) {
        DecodedJWT verify = JWT.require(Algorithm.HMAC256(TOKEN)).build().verify(token);
        return verify;
    }

}

/**
 * @Auther: xppll
 * @Date: 2021/11/26 14:07
 */
@RestController
@Slf4j
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping("/user/login")
    public Map<String, Object> login(User user) {
        Map<String, Object> map = new HashMap<>();
        try {
            User userDB = userService.login(user);
            //用來存放payload
            Map<String, String> payload = new HashMap<>();
            payload.put("id", userDB.getId());
            payload.put("name", userDB.getName());
            //生成JWT的令牌
            String token = JWTUtils.getToken(payload);
            map.put("state", true);
            map.put("msg", "成功");
            //成功返回token信息
            map.put("token", token);
        } catch (Exception e) {
            map.put("state", false);
            map.put("msg", e.getMessage());
        }
        return map;
    }
}

@PostMapping("user/test")
public Map<String, Object> test(String token) {
    //通過攔截器驗證了，token驗證成功
    Map<String, Object> map = new HashMap<>();
    map.put("state", true);
    map.put("msg", "請求成功！");
    return map;
}

/**
 * @Auther: xppll
 * @Date: 2021/11/26 15:20
 */
@Component
public class JWTInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        //獲取請求頭中存放的令牌token
        String token = request.getHeader("token");
        Map<String, Object> map = new HashMap<>();
        try {
            //驗證令牌
            JWTUtils.verify(token);
            return true;
        } catch (SignatureVerificationException e) {
            e.printStackTrace();
            map.put("msg", "無效簽名");
        } catch (AlgorithmMismatchException e) {
            e.printStackTrace();
            map.put("msg", "token算法不一致");
        } catch (TokenExpiredException e) {
            e.printStackTrace();
            map.put("msg", "token過期");
        } catch (Exception e) {
            e.printStackTrace();
            map.put("msg", "token無效");
        }

        map.put("state", false);
        //將map轉(zhuǎn)為json，返回給前端
        String json = new ObjectMapper().writeValueAsString(map);
        response.setContentType("application/json;charset=utf-8");
        response.getWriter().print(json);
        return false;
    }
}

/**
 * @Auther: xppll
 * @Date: 2021/11/26 15:28
 */
@Configuration
public class InterceptorConfig implements WebMvcConfigurer {
    @Autowired
    private JWTInterceptor jwtInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(jwtInterceptor)
                //其他接口需要token驗證，攔截器攔截
                .addPathPatterns("/user/test")
                .excludePathPatterns("/user/login");
    }
}