SpringBoot整合JWT实现登录认证

1、JWT的构成

• 头部(header):描述该JWT的最基本的信息，如类型以及签名所用的算法。
• 负载(payload):存放有效信息的地方。
• 签证(signature):base64加密后的header、base64加密后的payload和密钥secret加密后组成。

2、整合JWT

2.1 引入JWT依赖

<dependency>
      <groupId>com.auth0</groupId>
      <artifactId>java-jwt</artifactId>
      <version>3.18.3</version>
</dependency>

2.2 编写JWTUtils工具类

package com.stock.utils;
import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTCreator;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.interfaces.DecodedJWT;
import com.auth0.jwt.interfaces.Verification;
import java.util.Calendar;
import java.util.Map;

public class JWTUtils {
    private static  final String SING="@#$%^&*";
	//    生成token
    public static String getToken(Map<String,String> map){
        Calendar instance = Calendar.getInstance();
        instance.add(Calendar.MINUTE,30);
        //创建jwt builder
        JWTCreator.Builder builder = JWT.create();
        //payload
        builder.withExpiresAt(instance.getTime());
        map.forEach((k,v)->{
            builder.withClaim(k,v);
        });
        //设置签名
        String token = builder.sign(Algorithm.HMAC256(SING));
        return token;
    }
    //验证令牌
    public static void verifyToken(String token){
        JWTVerifier require = JWT.require(Algorithm.HMAC256(SING)).build();
        require.verify(token);
    }
    //获取token信息
    public static DecodedJWT getTokenInfo(String token){
        DecodedJWT verify = JWT.require(Algorithm.HMAC256(SING)).build().verify(token);
        return verify;
    }
}

2.3 编写拦截器

public class JWTInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        HashMap<String, Object> map = new HashMap<>();
        String token = request.getHeader("token");
        try {
            JWTUtils.verifyToken(token);
            return true;
        }catch (SignatureVerificationException e){
            map.put("msg","无效签名!");
        }catch (TokenExpiredException e){
            map.put("msg","token过期!");
        }catch (AlgorithmMismatchException e){
            map.put("msg","token加密算法不一致");
        }catch (Exception e){
            map.put("msg","无效签名!");
        }
        map.put("state",404);
        map.put("path","/login");
		//将map转化为字符串返回给前端
        String result = new ObjectMapper().writeValueAsString(map);
        response.setContentType("application/json;charset=UTF-8");
        response.getWriter().println(result);
        return false;
    }
}

注：token存放在请求的header中

2.4 配置拦截器

package com.stock.config;
import com.stock.Interceptors.JWTInterceptor;
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 IntercepterConfg implements WebMvcConfigurer {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new JWTInterceptor())
                .addPathPatterns("/**")
                .excludePathPatterns("/login");
    }
}

2.5 编写Controller

package com.stock.controller;
import com.stock.entity.User;
import com.stock.result.Result;
import com.stock.service.UserService;
import com.stock.utils.JWTUtils;
import com.stock.utils.ResultUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import java.util.HashMap;

@RestController
public class LoginController {
    private UserService userService;
    @Autowired
    public LoginController(UserService userService) {
        this.userService = userService;
    }

    @PostMapping("/login")
    public Result register(User user){
        HashMap<String, String> map = new HashMap<>();
        map.put("username",user.getUserName());
        String token = JWTUtils.getToken(map);
        HashMap<String, Object> data = new HashMap<>();
        data.put("token",token);
        return ResultUtils.getresult(200,"登录成功!",data);
    }
    @GetMapping("/main")
    public Result tomain(){
        return ResultUtils.getresult(200,"访问成功",null);
    }
}

2.6使用Postman测试

• 未登录前访问127.0.0.1:8888/main

• 先登录再访问127.0.0.1:8888/main