通过FeignClient路由至Spring Cloud API Gateway实现JWT授权问题

你的Feign调用之所以未生效，核心原因是Feign默认不会自动传递当前请求的Authorization头（即JWT Token），导致网关的AuthorizationHeaderFilter拿不到Token，验证不通过，请求被拦截。

下面提供两种可行的实现方式，让Feign调用携带JWT Token经过网关验证：

方式一：手动传递Authorization头 #

直接在Feign接口方法中添加@RequestHeader参数，调用时从当前请求中获取Token传入：

1. 修改Feign接口 #

@FeignClient(name = "RATING-SERVICE", url="http://localhost:9000")
public interface RatingService {

    @GetMapping("/ratingsdata/{managerInput}/{peerInput}/{dept}")
    Double getRating(
        @RequestHeader("Authorization") String authorizationHeader,
        @PathVariable Double managerInput, 
        @PathVariable Double peerInput,
        @PathVariable String dept);
}

2. 在调用处传入Token #

@Autowired
private RatingService ratingService;
@Autowired
private HttpServletRequest request;

// 从当前请求中获取Authorization头，传入Feign调用
Double empRating = ratingService.getRating(
    request.getHeader("Authorization"),
    employee.getManagerPoints(), 
    employee.getPeersPoints(), 
    employee.getDepartment().getDeptName());

方式二：全局自动传递Token（推荐） #

实现Feign的RequestInterceptor，自动从当前请求上下文提取Authorization头并添加到Feign请求中，无需手动传递：

1. 创建Feign请求拦截器 #

import feign.RequestInterceptor;
import feign.RequestTemplate;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import javax.servlet.http.HttpServletRequest;

@Component
public class FeignAuthInterceptor implements RequestInterceptor {

    @Override
    public void apply(RequestTemplate template) {
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        if (attributes != null) {
            HttpServletRequest request = attributes.getRequest();
            String authorization = request.getHeader("Authorization");
            if (authorization != null) {
                template.header("Authorization", authorization);
            }
        }
    }
}

2. 简化Feign接口 #

拦截器生效后，Feign接口无需额外参数，保持原有写法即可：

@FeignClient(name = "RATING-SERVICE", url="http://localhost:9000")
public interface RatingService {

    @GetMapping("/ratingsdata/{managerInput}/{peerInput}/{dept}")
    Double getRating(@PathVariable Double managerInput, @PathVariable Double peerInput,
            @PathVariable String dept);
}

• 避免硬编码网关地址：可以将网关注册到Eureka，Feign直接调用网关的服务名API-GATEWAY，替换硬编码的url="http://localhost:9000"，提升架构灵活性：

  @FeignClient(name = "API-GATEWAY")
  public interface RatingService {
      // ... 方法不变
  }
  

• 异步场景处理：如果是异步调用，需要手动传递请求上下文，否则RequestContextHolder会无法获取到当前请求，导致Token无法传递。

内容的提问来源于stack exchange，提问作者Ambrish Mayank