eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.//頭部
eyJpZCI6IjIiLCJleHAiOjE3MDI0NDE3MDcsInVzZXJuYW1lIjoiYWRtaW4ifQ.//負(fù)載
k8F9h5GQB1-rTVi-8hs9jOWnfpJALSk2Y08xeZb7YlE//簽名

<dependency>
     <groupId>com.auth0</groupId>
     <artifactId>java-jwt</artifactId>
     <version>3.4.1</version>
</dependency>

package com.hyh.util;

import com.auth0.jwt.JWT;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.interfaces.DecodedJWT;
import com.hyh.domain.User;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.util.Calendar;
import java.util.Date;

public class JwtUtil {
    // 生成token
    // Algorithm.HMAC256():使用HS256生成token,密鑰則是用戶的密碼
    private static final String SING = "MusicProject";

    public String getToken(User user) {
        //System.out.println(String.valueOf(user.getId()));
        // 設(shè)置token過期時(shí)間
        Calendar instance= Calendar.getInstance();
        instance.add(Calendar.DATE,7);
        String token="";
        token= JWT.create()
                .withClaim("id",String.valueOf(user.getId())) //設(shè)置載荷
                .withClaim("username",user.getUsername())
                .withExpiresAt(instance.getTime()) //設(shè)置令牌過期的時(shí)間
                .sign(Algorithm.HMAC256(SING));

        return token;
    }
    /**，
     * 驗(yàn)證token  合法性
     */
    public static DecodedJWT verify(String token) {
        return JWT.require(Algorithm.HMAC256(SING)).build().verify(token);
    }
}

public class AuthenticationInterceptor implements HandlerInterceptor {
    @Autowired
    UserService userService;

    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object object) throws Exception {
        String token = httpServletRequest.getHeader("token");// 從 http 請(qǐng)求頭中取出 token
        // 如果不是映射到方法直接通過
        if (!(object instanceof HandlerMethod)) {
            return true;
        }
        HandlerMethod handlerMethod = (HandlerMethod) object;
        Method method = handlerMethod.getMethod();

        //檢查有沒有需要用戶權(quán)限的注解
        if (method.isAnnotationPresent(TokenRequired.class)) {
            TokenRequired userLoginToken = method.getAnnotation(TokenRequired.class);
            if (userLoginToken.required()) {

                Map<String,Object> map = new HashMap<>();
                // 獲取請(qǐng)求頭中令牌
                System.out.println(token);
                try {
                    // 驗(yàn)證令牌
                    JwtUtil.verify(token);
                    return true;  // 放行請(qǐng)求
                } catch (SignatureVerificationException e) {
                    e.printStackTrace();
                    map.put("msg","無效簽名！");
                }catch (TokenExpiredException e){
                    e.printStackTrace();
                    map.put("msg","token過期");
                }catch (AlgorithmMismatchException e){
                    e.printStackTrace();
                    map.put("msg","算法不一致");
                }catch (Exception e){
                    e.printStackTrace();
                    map.put("msg","token無效！");
                }
                map.put("state",false);  //設(shè)置狀態(tài)
                // 將map以json的形式響應(yīng)到前臺(tái)  map --> json  (jackson)
                String json = new ObjectMapper().writeValueAsString(map);
                httpServletResponse.setContentType("application/json;charset=UTF-8");
                httpServletResponse.getWriter().println(json);
                return false;

            }
        }
        return true;
    }

@Configuration  // 配置類
public class InterceptorConfig implements WebMvcConfigurer {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new AuthenticationInterceptor())
                .addPathPatterns("/api/**")  // 攔截所有請(qǐng)求
                .excludePathPatterns("/api/login","/api/register");  // 放行登錄 注冊(cè)
    }
}

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface TokenRequired {
    boolean required() default true;
}

/*
     * @description: 用戶的登錄
     * @param: User user
     * @return:result
     * @author
     * @date: 2023/9/28 10:03
     */
    @PostMapping("/login")
    public Result login(@RequestBody User user,HttpSession httpSession,HttpServletResponse response){
        String checkCode = (String) httpSession.getAttribute("checkCode");
        System.out.println(checkCode);
        if (user.getCheCode() == null || !user.getCheCode().equalsIgnoreCase(checkCode)) {
            return new Result(Code.Err, null, "驗(yàn)證碼錯(cuò)誤");
        }

        boolean flag = userService.selectUsernamePwd(user);
        boolean is_exist = userService.selectByName(user.getUsername());
        if (flag) {
            JwtUtil jwtUtil = new JwtUtil();
            User user1 = userService.selectByNameToken(user.getUsername());
            String token = jwtUtil.getToken(user1);
            user.setToken(token);
            Cookie cookie = new Cookie("username",user.getUsername());
            cookie.setMaxAge(60*60*24*7);
            cookie.setPath("/");
            response.addCookie(cookie);
            httpSession.setAttribute("username", user.getUsername());
            return new Result(Code.Ok,user,"登錄成功");
        }else if(!is_exist){
            return new Result(Code.Err,user,"登錄失敗 用戶不存在");
        }else{
            return new Result(Code.Err,user,"登錄失敗");
        }
    }

   @GetMapping
    @TokenRequired
    public Result selectAllSingers(HttpServletRequest request) {
        List<Singer> singers = songService.selectSingerAll();
        Integer code = singers != null ? Code.Ok : Code.Err;
        String msg = singers != null ? "" : "數(shù)據(jù)查詢失敗 請(qǐng)重試";
        return new Result(code, singers, msg);
    }