SpringCloud Feign调用，传递header、token等参数

在SpringCloud的feign的调用过程中，我们可能需要传递token，header等数据，可以用feign的RequestInterceptor拦截器去处理,直接撸代码吧。

package com.fk.mgmg.interceptor;

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

import javax.servlet.http.HttpServletRequest;
import java.util.Enumeration;
import java.util.LinkedHashMap;
import java.util.Map;

/**
 * feign 统一token拦截器
 */
@Component
@Slf4j
public class FeignTokenInterceptor implements RequestInterceptor {
    @Override
    public void apply(RequestTemplate requestTemplate) {
        if(null == getHttpServletRequest() ) {
//            throw new ServiceException("403", "noTokenRequestHeader");
            log.error("noTokenRequestHeader");
            return;
        }
        String userId = getHttpServletRequest().getHeader("userId");
//        requestTemplate.header("userId", getHeaders(getHttpServletRequest()).get("userId"));
        requestTemplate.header("userId", userId);
        requestTemplate.header("token", getHeaders(getHttpServletRequest()).get("token"));
    }

    private HttpServletRequest getHttpServletRequest() {
        try {
        return ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
        } catch (Exception e) {
//            e.printStackTrace();
            return null;
        }
    }

    /**
     * Feign拦截器拦截请求获取Token对应的值
     * @param request
     * @return
     */
    private Map<String, String> getHeaders(HttpServletRequest request) {
        Map<String, String> map = new LinkedHashMap<>();
        Enumeration<String> enumeration = request.getHeaderNames();
        while (enumeration.hasMoreElements()) {
            String key = enumeration.nextElement();
            String value = request.getHeader(key);
            map.put(key, value);
        }
        return map;
    }
}