Feign設置Header頭部,@Headers無效

在使用FeignClient調用外部接口的時候，需要在請求頭部添加header的參數，用於請求的認證。在查找Feign文檔中提供了@Headers註解，該註解可以完成頭部的添加。但是卻沒有生效

@FeignClient(name="name",url = "127.0.0.1:8090/test",path = "/")
public interface IUserService {

    @RequestMapping(value = "getUserPage",method = RequestMethod.POST)
    @Headers(value={"ContentType=application/x-www-form-urlencoded","Inner_token=PXH0dP5I8qQ8UbFPpzm67cQkm7j8tWT2Kwn6J6SXYkfp2kMo/lSqHQ=="})
    public Map<String,Object> getUserPage(User user);
}

在服務端獲取不到Inner_token的頭部參數。得到的結果是null

於是開啓feign的日誌

第一步：定義feign的日誌配置文件類

@Configuration
public class FeignConfig {

    @Bean
    Logger.Level feignLevel(){
        return Logger.Level.FULL;
    }
}

第二步：在調用的FeignClien客戶端註解上指定該日誌級別配置文件

@FeignClient(name="name",url = "127.0.0.1:8090/test",path = "/",configuration = FeignConfig.class)
public interface IUserService {

    @RequestMapping(value = "getUserPage",method = RequestMethod.POST)
    @Headers(value={"ContentType=application/x-www-form-urlencoded","Inner_token=PXH0dP5I8qQ8UbFPpzm67cQkm7j8tWT2Kwn6J6SXYkfp2kMo/lSqHQ=="})
    public Map<String,Object> getUserPage(User user);
}

第三步：配置yml文件，指定該feignclient的配置路徑和日誌級別

logging:
  level:
    demo.IUserService: debug

重啓，併發起請求

2019-09-27 10:46:01.662 DEBUG 15200 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] ---> POST http://127.0.0.1:8090/test/getUserPage HTTP/1.1
2019-09-27 10:46:01.663 DEBUG 15200 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] Content-Type: application/json;charset=UTF-8
2019-09-27 10:46:01.663 DEBUG 15200 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] Content-Length: 53
2019-09-27 10:46:01.663 DEBUG 15200 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] 
2019-09-27 10:46:01.663 DEBUG 15200 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] {"id":0,"tableName":"feignTable","page":10,"size":10}
2019-09-27 10:46:01.663 DEBUG 15200 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] ---> END HTTP (53-byte body)
2019-09-27 10:46:01.684 DEBUG 15200 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] <--- HTTP/1.1 200 (21ms)
2019-09-27 10:46:01.684 DEBUG 15200 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] content-type: application/json;charset=UTF-8
2019-09-27 10:46:01.685 DEBUG 15200 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] date: Fri, 27 Sep 2019 02:46:01 GMT
2019-09-27 10:46:01.685 DEBUG 15200 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] transfer-encoding: chunked
2019-09-27 10:46:01.685 DEBUG 15200 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] x-application-context: HelloServer:8090
2019-09-27 10:46:01.685 DEBUG 15200 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] 
2019-09-27 10:46:01.689 DEBUG 15200 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] {"success":true,"rows":[{"id":10111,"tableName":"hbaseTable","page":1,"size":20},{"id":10112,"tableName":"hbaseTable","page":1,"size":20},{"id":10113,"tableName":"hbaseTable","page":1,"size":20},{"id":10114,"tableName":"hbaseTable","page":1,"size":20},{"id":10115,"tableName":"hbaseTable","page":1,"size":20},{"id":10116,"tableName":"hbaseTable","page":1,"size":20},{"id":10117,"tableName":"hbaseTable","page":1,"size":20},{"id":10118,"tableName":"hbaseTable","page":1,"size":20},{"id":10119,"tableName":"hbaseTable","page":1,"size":20},{"id":10120,"tableName":"hbaseTable","page":1,"size":20}]}
2019-09-27 10:46:01.689 DEBUG 15200 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] <--- END HTTP (595-byte body)

在日誌中發現，header中沒有被加上我之前設置的參數。說明該註解沒有生效

於是debug調試

通過debug我發現feign會先將請求參數構建成Request對象，request信息如下：

從圖中可看到，該Request實例的headers屬性爲空，而Request又是根據RequestTemplate模板對象生成的，RequestTemplate實例信息如下：

到這裏可以看出，問題是出在RequestTemplate的構建構成中，於是我就去跟蹤RequestTemplate構建的代碼，發現RequestTemplate是根據MethodMetadata構建而成，而MethodMetadata就是對方法配置的抽象。

RequestTemplate template = resolve(argv, mutable, varBuilder);
      if (metadata.queryMapIndex() != null) {
        // add query map parameters after initial resolve so that they take
        // precedence over any predefined values
        template = addQueryMapQueryParameters(argv, template);
      }

      if (metadata.headerMapIndex() != null) {
        template = addHeaderMapHeaders(argv, template);
      }

從上述代碼可以看到，header的設置是由metadata的headerMapIndex 屬性決定的，那麼，設置headerMapIndex的位置，必然就和Header的解析相關，於是通過查看方法引用，我找到了下面的代碼：

private void parseHeaders(MethodMetadata md, Method method,
            RequestMapping annotation) {
        // TODO: only supports one header value per key
        if (annotation.headers() != null && annotation.headers().length > 0) {
            for (String header : annotation.headers()) {
                int index = header.indexOf('=');
                if (!header.contains("!=") && index >= 0) {
                    md.template().header(resolve(header.substring(0, index)),
                        resolve(header.substring(index + 1).trim()));
                }
            }
        }
    }

從代碼中我們可以清晰的看到，解析過程中是從@RequestMapping或其派生註解的header屬性中解析Header的，並且Header的key和value需要用“=”進行分割。
於是我修改成下面的形式，問題就解決了：

@FeignClient(name="name",url = "127.0.0.1:8090/test",path = "/",configuration = FeignConfig.class)
public interface IUserService {

    @RequestMapping(value = "getUserPage",method = RequestMethod.POST,headers = {"ContentType=application/x-www-form-urlencoded","Inner_token=PXH0dP5I8qQ8UbFPpzm67cQkm7j8tWT2Kwn6J6SXYkfp2kMo/lSqHQ=="})
    @Headers(value={"ContentType=application/x-www-form-urlencoded","Inner_token=PXH0dP5I8qQ8UbFPpzm67cQkm7j8tWT2Kwn6J6SXYkfp2kMo/lSqHQ=="})
    public Map<String,Object> getUserPage(User user);
}

查看請求日誌

2019-09-27 11:10:29.975 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] ---> POST http://127.0.0.1:8090/test/getUserPage HTTP/1.1
2019-09-27 11:10:29.976 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] ContentType: application/x-www-form-urlencoded
2019-09-27 11:10:29.976 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] Inner_token: PXH0dP5I8qQ8UbFPpzm67cQkm7j8tWT2Kwn6J6SXYkfp2kMo/lSqHQ==
2019-09-27 11:10:29.976 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] Content-Type: application/json;charset=UTF-8
2019-09-27 11:10:29.976 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] Content-Length: 53
2019-09-27 11:10:29.976 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] 
2019-09-27 11:10:29.976 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] {"id":0,"tableName":"feignTable","page":10,"size":10}
2019-09-27 11:10:29.976 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] ---> END HTTP (53-byte body)
2019-09-27 11:10:29.992 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] <--- HTTP/1.1 200 (16ms)
2019-09-27 11:10:29.993 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] content-type: application/json;charset=UTF-8
2019-09-27 11:10:29.993 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] date: Fri, 27 Sep 2019 03:10:29 GMT
2019-09-27 11:10:29.993 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] transfer-encoding: chunked
2019-09-27 11:10:29.993 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] x-application-context: HelloServer:8090
2019-09-27 11:10:29.993 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] 
2019-09-27 11:10:29.995 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] {"success":true,"rows":[{"id":10141,"tableName":"hbaseTable","page":1,"size":20},{"id":10142,"tableName":"hbaseTable","page":1,"size":20},{"id":10143,"tableName":"hbaseTable","page":1,"size":20},{"id":10144,"tableName":"hbaseTable","page":1,"size":20},{"id":10145,"tableName":"hbaseTable","page":1,"size":20},{"id":10146,"tableName":"hbaseTable","page":1,"size":20},{"id":10147,"tableName":"hbaseTable","page":1,"size":20},{"id":10148,"tableName":"hbaseTable","page":1,"size":20},{"id":10149,"tableName":"hbaseTable","page":1,"size":20},{"id":10150,"tableName":"hbaseTable","page":1,"size":20}]}
2019-09-27 11:10:29.995 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService                        : [IUserService#getUserPage] <--- END HTTP (595-byte body)

請求中header已經被成功添加