1.jwt简介

• JWT: Json Web Token
• 官网： https://jwt.io/

2.使用jwt

2.1添加依赖

<!-- https://mvnrepository.com/artifact/com.auth0/java-jwt -->
<dependency>
    <groupId>com.auth0</groupId>
    <artifactId>java-jwt</artifactId>
    <version>3.10.3</version>
</dependency>

<!-- https://mvnrepository.com/artifact/io.jsonwebtoken/jjwt -->
<dependency>
    <groupId>io.jsonwebtoken</groupId>
    <artifactId>jjwt</artifactId>
    <version>0.9.1</version>
</dependency>

2.2 生成token

            // 使用jwt规则生成token字符串
            JwtBuilder builder = Jwts.builder();

            HashMap<String,Object> map = new HashMap<>();

            String token = builder.setSubject(phone) // 主题，token携带的数据
                    .setIssuedAt(new Date()) // 设置token的生成时间
                    .setId(users.get(0).getUserId() + "") // 设置用户id为tokenid
                    .setClaims(map) // map中存放用户的角色权限信息
                    .setExpiration(new Date(System.currentTimeMillis() + 24 * 60 * 60 * 1000)) // 设置token过期时间
                    .signWith(SignatureAlgorithm.HS256, Base64Utils.stringcode) // 设置加密方式和加密密码
                    .compact();

2.3 校验token

        // 验证token
        JwtParser parser = Jwts.parser();
        // 解析token的SiginKey必须和生成token时设置密码时的一致
        parser.setSigningKey(Base64Utils.stringcode);

        try {
            // 如果token正确（密码正确，有效期内）则正常执行，否则抛出异常
            Jws<Claims> claimsJws = parser.parseClaimsJws(token);

            // 获取token中用户数据
            Claims body = claimsJws.getBody();
            /// 获取生成token设置的subject
            String subject = body.getSubject();
            // 获取生成token时存储的Claim的map中的值,其中key1为map中的键
            String key1 = body.get("key1", String.class);
            // 验证成功，进行之后的处理
        } catch (Exception e) {
            // 对于密码不正确/token过期的处理
            System.out.println(e);
        }

2.4 拦截器校验Token

• 创建拦截器

package com.computerskills.competition.interceptor;


import com.computerskills.competition.utils.Base64Utils;
import com.computerskills.competition.vo.ResStatus;
import com.computerskills.competition.vo.ResultVo;
import com.fasterxml.jackson.databind.ObjectMapper;
import io.jsonwebtoken.*;
import lombok.SneakyThrows;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.image.RescaleOp;
import java.io.IOException;
import java.io.PrintWriter;

@Component
public class CheckTokenInterceptor implements HandlerInterceptor {


    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        String method = request.getMethod();
        // 针对于预检请求
        if ("OPTIONS".equalsIgnoreCase(method)) {
            return true;
        }
        String token = request.getHeader("token");
        if(token == null) {
            doResponse(response,new ResultVo(ResStatus.Err,"请先登录",null));
        } else {
            try {
                // 验证token
                JwtParser parser = Jwts.parser();
                // 解析token的SiginKey必须和生成token时设置密码时的一致
                parser.setSigningKey(Base64Utils.stringcode);
                // 如果token正确（密码正确，有效期内）则正常执行，否则抛出异常
                Jws<Claims> claimsJws = parser.parseClaimsJws(token);
                return true;
            } catch (ExpiredJwtException e) {
                doResponse(response,new ResultVo(ResStatus.Err,"登录已过期，请重新登录",null));
            } catch (UnsupportedJwtException e) {
                doResponse(response,new ResultVo(ResStatus.Err,"Token不合法",null));
            } catch (Exception e) {
                doResponse(response,new ResultVo(ResStatus.Err,"请先登录",null));
            }
        }
        return false;
    }


    private void doResponse(HttpServletResponse response, ResultVo resultVo) throws IOException {
        response.setContentType("application/json");
        response.setCharacterEncoding("utf-8");
        PrintWriter writer = response.getWriter();
        String s = new ObjectMapper().writeValueAsString(resultVo);
        writer.print(s);
        writer.flush();
        writer.close();
    }
}

• 配置拦截器

package com.computerskills.competition.config;


import com.computerskills.competition.interceptor.CheckTokenInterceptor;
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 CheckTokenInterceptor checkTokenInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        // 添加拦截器到mvc中
        registry.addInterceptor(checkTokenInterceptor)
        .addPathPatterns("/role/**") // 拦截的路径-------路径不包括：context path '/used'
        .excludePathPatterns("/user/**"); // 不拦截的路径
    }
}