maven进入包

<!--    start    jwt引入-->

<dependency>

<groupId>io.jsonwebtoken</groupId>

<artifactId>jjwt</artifactId>

<version>0.9.1</version>

</dependency>

<!--    end    jwt引入-->

新建一个类ResultVO作为返回前端的类型

package com.bruce.vo;

import io.swagger.annotations.ApiModel;

import io.swagger.annotations.ApiModelProperty;

import lombok.AllArgsConstructor;

import lombok.Data;

import lombok.NoArgsConstructor;

import lombok.ToString;

/**

* @Auther:BruceWong

* @Date: 2021/6/16 - 06 - 16 - 11:15

* @Description:com.bruce.vo

* @Version: 1.0

*/

@Data

@NoArgsConstructor

@AllArgsConstructor

@ToString

@ApiModel(value = "响应的VO对象",description = "封装接口返回给前端的数据")

public class ResultVO {

    @ApiModelProperty("响应状态码")

    private int code;

    @ApiModelProperty("响应提示信息")

    private String msg;

    @ApiModelProperty("响应数据内容")

    private Object data;

}

新建一个类TokenInterceptor并实现HandlerInterceptor

package com.bruce.interceptor;

import com.bruce.vo.ResultStatus;

import com.bruce.vo.ResultVO;

import com.bruce.vo.TokenSecret;

import com.fasterxml.jackson.databind.ObjectMapper;

import io.jsonwebtoken.*;

import org.springframework.stereotype.Component;

import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

import java.io.PrintWriter;

@Component

public class TokenInterceptor implements HandlerInterceptor {

    @Override

    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

        String method = request.getMethod();

        if ("options".equalsIgnoreCase(method)) {

            return true;

        }

        String token = request.getHeader("token");

        if (token == null) {

            ResultVO resultVO = new ResultVO(ResultStatus.NO, "请先登录", null);

            doResponse(response, resultVO);

        } else {

            try {

                JwtParser parser = Jwts.parser();

                parser.setSigningKey(TokenSecret.SUFIX);

                Jws<Claims> claimsJws = parser.parseClaimsJws(token);

                return HandlerInterceptor.super.preHandle(request, response, handler);

            } catch (ExpiredJwtException e) {

                ResultVO resultVO = new ResultVO(ResultStatus.NO, "登录过期请重新登录", null);

                doResponse(response, resultVO);

            } catch (UnsupportedJwtException e) {

                ResultVO resultVO = new ResultVO(ResultStatus.NO, "Token不合法，请自重", null);

                doResponse(response, resultVO);

            } catch (Exception e) {

                ResultVO resultVO = new ResultVO(ResultStatus.NO, "请先登录", null);

                doResponse(response, resultVO);

            }

        }

        return false;

    }

    private void doResponse(HttpServletResponse response, ResultVO resultVO) throws IOException {

        response.setContentType("application/json");

        response.setCharacterEncoding("utf-8");

        PrintWriter out = response.getWriter();

        String s = new ObjectMapper().writeValueAsString(resultVO);

        out.print(s);

        out.flush();

        out.close();

    }

}

新建一个拦截器的配置类InterceptorConfig并实现WebMvcConfigurer接口

package com.bruce.config;

import com.bruce.interceptor.TokenInterceptor;

import org.springframework.beans.factory.annotation.Autowired;

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 {

    @Autowired

    private TokenInterceptor checkTokenInterceptor;

    @Override

    public void addInterceptors(InterceptorRegistry registry) {

        registry.addInterceptor(checkTokenInterceptor)

                .addPathPatterns("/shopcart/**").addPathPatterns("/order/**")  //设置要拦截过滤的请求url

                .excludePathPatterns("/user/**");                              //设置不要要拦截过滤的请求url

    }

}

配置过后，当请求/shopcart或/order路径下的内容的时候，就会过滤判断如果没有发现token或者token有问题则会被拦截