springboot中使用拦截器+Jwt+全局异常处理来拦截指定请求并分析token的正确与否返回给前端友好提示

1.我们先创建Jwt工具类来生成token，在往期文章中有给出代码

https://blog.youkuaiyun.com/m0_65206614/article/details/133747580?spm=1001.2014.3001.5501

2. 我们需要配置全局异常处理类，往期文章中给出了代码

https://blog.youkuaiyun.com/m0_65206614/article/details/133747390?spm=1001.2014.3001.5501

3. 设置拦截器规则

import com.xiaowei.exception.TokenException;
import com.xiaowei.utlis.JwtUtils;
import io.jsonwebtoken.Claims;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@Component
public class LoginInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("拦截器执行");
        String token=request.getHeader("token"); //获取请求头中的token
        if (!StringUtils.hasText(token)){
            throw new TokenException("token为空"); //这里抛出的异常会进入全局异常处理类
        }

        try{
            Claims claims = JwtUtils.parseToken(token); //对token进行解析
            String subject = claims.getSubject();
            System.out.println(subject);
        }catch (RuntimeException e){
            throw new TokenException("token异常");
        }
        return true; //拦截器 返回false就是拦截，返回true就是放行
    }
}

4.配置拦截器

import com.xiaowei.interceptor.LoginInterceptor;
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;

import java.util.function.LongToIntFunction;

@Configuration
public class LoginConfig implements WebMvcConfigurer {
    @Autowired
    private LoginInterceptor loginInterceptor; 
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(loginInterceptor) //配置拦截器规则
                .addPathPatterns("/**")  //配置拦截路径 /** 为所有路径
                .excludePathPatterns("/user/login"); //配置放行路径，可以配置多个，我们使用swagger的时候也需要把swagger的所有路径放行
    }
}