JWT--实现登录态

解析token

https://jwt.io/

https://blog.csdn.net/cxmengxin/article/details/119279848

maven依赖

    <dependency>
    <groupId>io.jsonwebtoken</groupId>
    <artifactId>jjwt</artifactId>
    <version>0.9.0</version>
    </dependency>

测试

package com;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.JwtBuilder;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;
import java.text.SimpleDateFormat;
import java.util.Date;

@SpringBootTest
class JjwtdemoApplicationTests {

//    创建token
    @Test
    public void testCreateToken(){
        //当前系统时间
        long now =System.currentTimeMillis();
//        过期时间一分钟
        long exp =now+60*1000;

        //创建JwtBuilder对象
        JwtBuilder jwtBuilder = Jwts.builder()
            //声明的标识{"jti":"8888"}
            .setId("8888")
            //主体,用户{"sub":"Rose"}
            .setSubject("Rose")
            //创建日期{"ita":"xxxxxx"}
            .setIssuedAt(new Date())
//                xxxx是盐
            .signWith(SignatureAlgorithm.HS256,"xxxx")
                //设置过期时间
            .setExpiration(new Date(exp))
            //自定义申明
            .claim("roles","admin")
            .claim("logo","xxx.jpg");
//                另外一种方法,直接传入map
//              .addClaims(map)

        //获取jwt的token
        String token = jwtBuilder.compact();
        System.out.println(token);

//        //解析token
//        System.out.println("=================");
//        String[] splist =token.split("\\.");
//        System.out.println(splist);
//        System.out.println(Base64Codec.BASE64.decodeToString(splist[0]));
//        System.out.println(Base64Codec.BASE64.decodeToString(splist[1]));
////        签名部分
//        System.out.println(Base64Codec.BASE64.decodeToString(splist[2]));
    }

    //    解析token
    @Test
    public void testParseToken(){
        String token="eyJhbGciOiJIUzI1NiJ9.eyJqdGkiOiI4ODg4Iiwic3ViIjoiUm9zZSIsImlhdCI6MTY0OTIzNDg3OSwiZXhwIjoxNjQ5MjM0OTM5LCJyb2xlcyI6ImFkbWluIiwibG9nbyI6Inh4eC5qcGcifQ.y3OQjS4kxRXU3NOcdNaCWT9_1M5sagQoUCqyfZc9_sU";
        //解析token
        Claims claims = Jwts.parser()
                .setSigningKey("xxxx")
                .parseClaimsJws(token)
                .getBody();
        System.out.println("id："+claims.getId());
        System.out.println("subject："+claims.getSubject());
        System.out.println("issuedAt："+claims.getIssuedAt());

        SimpleDateFormat simpleDateFormat= new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        System.out.println("签发时间："+simpleDateFormat.format(claims.getIssuedAt()));
        System.out.println("过期时间："+simpleDateFormat.format(claims.getExpiration()));
        System.out.println("当前时间："+simpleDateFormat.format(new Date()));
        //获取自定义
        System.out.println("roles："+claims.get("roles"));
        System.out.println("logo："+claims.get("logo"));


    }

程序员青戈 教的 https://www.bilibili.com/video/BV1U44y1W77D?p=16&vd_source=caabcbd2a759a67e2a3de8acbaaf08ea

<!-- JWT -->
<dependency>
<groupId>com.auth0</groupId>
<artifactId>java-jwt</artifactId>
<version>3.10.3</version>
</dependency>

目录:

control.    ----

@RestController
@RequestMapping("/user")
public class UserController {
@PostMapping("/login")
    public Result login(@RequestBody UserDTO userDTO) {
        String username = userDTO.getUsername();
        String password = userDTO.getPassword();
        if (StrUtil.isBlank(username) || StrUtil.isBlank(password)) {
            return Result.error(Constants.CODE_400, "参数错误");
        }
        UserDTO dto = userService.login(userDTO);
        return Result.success(dto);
    }
}

login的实现类代码         --------这里涉及统一规范接口返回信息:  https://www.cnblogs.com/kaibindirver/p/16358813.html

 @Override
    public UserDTO login(UserDTO userDTO) {
        User one = getUserInfo(userDTO);
        if (one != null) {
            BeanUtil.copyProperties(one, userDTO, true);
            // 设置token
            String token = TokenUtils.genToken(one.getId().toString(), one.getPassword());
            userDTO.setToken(token);

            String role = one.getRole(); // ROLE_ADMIN
            // 设置用户的菜单列表
            List<Menu> roleMenus = getRoleMenus(role);
            userDTO.setMenus(roleMenus);
            return userDTO;
        } else {
            throw new ServiceException(Constants.CODE_600, "用户名或密码错误");
        }
    }

TokenUtils

package com.qingge.springboot.utils;

import cn.hutool.core.date.DateUtil;
import cn.hutool.core.util.StrUtil;
import com.auth0.jwt.JWT;
import com.auth0.jwt.algorithms.Algorithm;
import com.qingge.springboot.entity.User;
import com.qingge.springboot.service.IUserService;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import java.util.Date;

@Component
public class TokenUtils {

    private static IUserService staticUserService;

    @Resource
    private IUserService userService;

    @PostConstruct
    public void setUserService() {
        staticUserService = userService;
    }   //静态方法不可使用非静态属性 所以要有这一步

    /**
     * 生成token
     *
     * @return
     */
    public static String genToken(String userId, String sign) {
        return JWT.create().withAudience(userId) // 将 user id 保存到 token 里面,作为载荷
                .withExpiresAt(DateUtil.offsetHour(new Date(), 60)) // 2小时后token过期
                .sign(Algorithm.HMAC256(sign)); // 以 password 作为 token 的密钥
    }

    /**
     * 获取当前登录的用户信息
     *
     * @return user对象
     */
    public static User getCurrentUser() {
        try {
            HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
            String token = request.getHeader("token");
            if (StrUtil.isNotBlank(token)) {
                String userId = JWT.decode(token).getAudience().get(0);
                return staticUserService.getById(Integer.valueOf(userId));
            }
        } catch (Exception e) {
            return null;
        }
        return null;
    }
}

InterceptorConfig

package com.qingge.springboot.config;

import com.qingge.springboot.config.interceptor.JwtInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class InterceptorConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(jwtInterceptor())
                .addPathPatterns("/**")  // 拦截所有请求，通过判断token是否合法来决定是否需要登录
                .excludePathPatterns("/user/login", "/user/register", "/**/export", "/**/import", "/file/**",
                        "/swagger-resources/**", "/webjars/**", "/v2/**", "/swagger-ui.html/**", "/api", "/api-docs", "/api-docs/**")
                .excludePathPatterns( "/**/*.html", "/**/*.js", "/**/*.css", "/**/*.woff", "/**/*.ttf");  // 放行静态文件

    }

    @Bean
    public JwtInterceptor jwtInterceptor() {
        return new JwtInterceptor();
    }

}

JwtInterceptor            ---------前端获取的token是存在localStorage里面 参考: https://www.cnblogs.com/kaibindirver/p/13674893.html

package com.qingge.springboot.config.interceptor;

import cn.hutool.core.util.StrUtil;
import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.exceptions.JWTVerificationException;
import com.qingge.springboot.common.Constants;
import com.qingge.springboot.config.AuthAccess;
import com.qingge.springboot.entity.User;
import com.qingge.springboot.exception.ServiceException;
import com.qingge.springboot.service.IUserService;
import com.qingge.springboot.utils.TokenUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class JwtInterceptor implements HandlerInterceptor {

    @Autowired
    private IUserService userService;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        String token = request.getHeader("token");

        // 如果不是映射到方法直接通过
        if(!(handler instanceof HandlerMethod)){
            return true;
        } else {
            HandlerMethod h = (HandlerMethod) handler;
            AuthAccess authAccess = h.getMethodAnnotation(AuthAccess.class);
            if (authAccess != null) {
                return true;
            }
        }
        // 执行认证
        if (StrUtil.isBlank(token)) {
            throw new ServiceException(Constants.CODE_401, "无token，请重新登录");
        }
        // 获取 token 中的 user id
        String userId;
        try {
            userId = JWT.decode(token).getAudience().get(0);
        } catch (JWTDecodeException j) {
            throw new ServiceException(Constants.CODE_401, "token验证失败，请重新登录");
        }
        // 根据token中的userid查询数据库
        User user = userService.getById(userId);
        if (user == null) {
            throw new ServiceException(Constants.CODE_401, "用户不存在，请重新登录");
        }
        // 用户密码加签验证 token
        JWTVerifier jwtVerifier = JWT.require(Algorithm.HMAC256(user.getPassword())).build();
        try {
            jwtVerifier.verify(token); // 验证token
        } catch (JWTVerificationException e) {
            throw new ServiceException(Constants.CODE_401, "token验证失败，请重新登录");
        }
//        获取用户信息,调用TokenUtils类里面的静态方法
        System.out.println(TokenUtils.getCurrentUser().getNickname()+"++++++++++++++++++++++");
        return true;
    }
}

上面的例子是用用户的密码做盐！ 其实可以写死一个，然后生产的令牌 其实可以再存一份到redis 然后，然后可以查询是否存在啥的，可以加了一层控制有效时间(手动删掉，查到不存在逼退) 和 单点多点登陆等操作(单点，存在这个user_id的token,再登陆就干掉重新写入一个)