通过Feign在服务之间传递header请求头信息

问题背景

paas服务发生异常日志报警时，需要在paas服务中把对应header信息打印出来，由于接口请求的是saas服务，所以saas调用paas时需要把hearer传递过去。

解决办法

新增Feign的配置类，实现RequestInterceptor接口中的apply方法。

@Slf4j
public class FeignConfig implements RequestInterceptor {

    @Override
    public void apply(RequestTemplate requestTemplate) {
        HttpServletRequest httpServletRequest = this.getHttpServletRequest();
        log.info("RequestTemplate.headers:" + JSON.toJSONString(requestTemplate.headers()));
        if (null != httpServletRequest) {
            Map<String, String> headers = getHeaders(httpServletRequest);
            for (Map.Entry<String, String> entry : headers.entrySet()) {
                requestTemplate.header(entry.getKey(), entry.getValue());
            }
        }
    }

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

    private Map<String, String> getHeaders(HttpServletRequest request) {
        Map<String, String> map = new LinkedHashMap<>();
        Enumeration<String> enumeration = request.getHeaderNames();
        if (enumeration != null) {
            while (enumeration.hasMoreElements()) {
                String key = enumeration.nextElement();
                String value = request.getHeader(key);
                map.put(key, value);
            }
        }
        return map;
    }
}