bug记录（feign）——如何给feign加上请求头相关的参数，让生产者获得请求头中参数

问题描述

在微服务的调用中，如果消费者通过feign调用生产者，然后生产者方法中需要用到请求头，从请求头中获得token，但是feign默认是不携带请求头的，因此即使消费者请求feign的时候请求头中携带了token，也没有传到生产者，就会报相关的错误。

解决方案

1.如果token直接在请求头中

解决方案：加一个拦截器

package com.tianju.rabbit.feign.interceptor;

import feign.RequestInterceptor;
import feign.RequestTemplate;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.http.HttpServletRequest;

@Configuration
@Slf4j
public class FeignInterceptor implements RequestInterceptor {
    @Override
    public void apply(RequestTemplate requestTemplate) {
        // 获取 HttpServletRequest
        ServletRequestAttributes attributes = (ServletRequestAttributes)
                RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();

        String token = request.getHeader("token");
        if (null!=token && !"".equals(token)){
            log.info(">>> feign拦截器获取token：{}",token);
            requestTemplate.header("token", token);
        }
    }
}

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2.如果token在cookie里面

代码需要稍微做些修改

package com.tianju.rabbit.feign.interceptor;

import feign.RequestInterceptor;
import feign.RequestTemplate;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;

@Configuration
@Slf4j
public class FeignInterceptor implements RequestInterceptor {
    @Override
    public void apply(RequestTemplate requestTemplate) {
        // 获取 HttpServletRequest
        ServletRequestAttributes attributes = (ServletRequestAttributes)
                RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();

        Cookie[] cookies = request.getCookies();
        for(Cookie cookie:cookies){
            if ("token".equals(cookie.getName())){
                // 把TOKEN带到下服务（token消息加到头消息）
                log.debug(">>>> feign的拦截器，获取token："+cookie.getValue());
                requestTemplate.header("token",cookie.getValue());
            }
        }
    }
}
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总结

给feign加一个拦截器，设置一下请求头。