/** Feign 調(diào)用的時候傳token到下游 */
public class FeignRequestInterceptor implements RequestInterceptor {
  @Override
  public void apply(RequestTemplate template) {
    // 從header獲取X-token
    RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
    ServletRequestAttributes attr = (ServletRequestAttributes) requestAttributes;
    HttpServletRequest request = attr.getRequest();
    String token = request.getHeader("x-auth-token");//網(wǎng)關(guān)傳過來的 token
    if (StringUtils.hasText(token)) {
      template.header("X-AUTH-TOKEN", token);
    }
  }
}

@FeignClient(
    ...
    configuration = {FeignClientDecoderConfiguration.class, FeignRequestInterceptor.class})
public interface AuthCenterClient {

public static RequestAttributes getRequestAttributes() {
   RequestAttributes attributes = requestAttributesHolder.get();
   if (attributes == null) {
      attributes = inheritableRequestAttributesHolder.get();
   }
   return attributes;
}

/**
 * 給當(dāng)前線程綁定屬性
 * @param inheritable 是否要將屬性暴露給子線程
 */
public static void setRequestAttributes(@Nullable RequestAttributes attributes, boolean inheritable) {
   //......
}

RequestContextHolder.setRequestAttributes(RequestContextHolder.getRequestAttributes(), true);
log.info("主線程任務(wù)....");
new Thread(() -> {
    log.info("子線程任務(wù)開始...");
    UserResponse response = client.getById(3L);
}).start();

//...
Thread parent = currentThread(); //創(chuàng)建子線程的時候先拿父線程
//...
if (inheritThreadLocals && parent.inheritableThreadLocals != null)
 this.inheritableThreadLocals = ThreadLocal.createInheritedMap(parent.inheritableThreadLocals;
//...

@GetMapping("/test")
public void test(HttpServletRequest request) {
    RequestAttributes attr = RequestContextHolder.getRequestAttributes();
    log.info("父線程:RequestAttributes:{}", attr);
    RequestContextHolder.setRequestAttributes(attr, true);
    log.info("父線程:SpringMVC:request:{}",request);
    log.info("父線程:x-auth-token:{}",request.getHeader("x-auth-token"));
    ServletRequestAttributes attr1 = (ServletRequestAttributes) attr;
    HttpServletRequest request1 = attr1.getRequest();
    log.info("父線程:request:{}",request1);
    new Thread(
            () -> {
                try {
                    TimeUnit.SECONDS.sleep(3);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                RequestAttributes childAttr = RequestContextHolder.getRequestAttributes();
                log.info("子線程:RequestAttributes:{}",childAttr);
                ServletRequestAttributes childServletRequestAttr = (ServletRequestAttributes) childAttr;
                HttpServletRequest childRequest = childServletRequestAttr.getRequest();
                log.info("子線程:childRequest:{}",childRequest);
                String childToken = childRequest.getHeader("x-auth-token");
                log.info("子線程:x-auth-token:{}",childToken);
            }).start();
}

父線程:RequestAttributes:org.apache.catalina.connector.RequestFacade@ea25271
父線程:SpringMVC:request:org.apache.catalina.connector.RequestFacade@ea25271
父線程:x-auth-token:null
父線程:request:org.apache.catalina.connector.RequestFacade@ea25271

子線程:RequestAttributes:org.apache.catalina.connector.RequestFacade@ea25271
子線程:childRequest:org.apache.catalina.connector.RequestFacade@ea25271
子線程:x-auth-token:{}:null

public class RequestHeaderHolder {
    private static final ThreadLocal<Map<String,String>> REQUEST_HEADER_HOLDER = new InheritableThreadLocal<>(){
        @Override
        protected Map<String, String> initialValue() {
            return new HashMap<>();
        }
    };
    //...省略部分方法
}

public class RequestHeaderInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        Enumeration<String> headerNames = request.getHeaderNames();

        while (headerNames.hasMoreElements()){
            String s = headerNames.nextElement();
            RequestHeaderHolder.set(s,request.getHeader(s));
        }
        return true;
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        RequestHeaderHolder.remove(); //注意一定要remove
    }
}