使用feign服务调用添加Header参数

feign添加Header参数
@Configuration
public class FeignConfiguration implements RequestInterceptor { 
 private static final Logger logger = LoggerFactory.getLogger(FeignConfiguration.class);
 
 @Override
 public void apply(RequestTemplate template) {
  ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
  if(null != attributes) {
   HttpServletRequest request = attributes.getRequest();
         String token = request.getHeader("token");
         template.header("token", token);
  }
        logger.info("feign interceptor header:{}",template);
 }
}
Feign设置Header头部,@Headers无效
在使用FeignClient调用外部接口的时候，需要在请求头部添加header的参数，用于请求的认证。在查找Feign文档中提供了@Headers注解，该注解可以完成头部的添加。但是却没有生效
@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);
}
在服务端获取不到Inner_token的头部参数。得到的结果是null
于是开启feign的日志
第一步：定义feign的日志配置文件类
@Configuration
public class FeignConfig {
    @Bean
    Logger.Level feignLevel(){
        return Logger.Level.FULL;
    }
}
第二步：在调用的FeignClien客户端注解上指定该日志级别配置文件
@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，指定该feignclient的配置路径和日志级别
logging:
  level:
    demo.IUserService: debug
重启，并发起请求
2019-09-27 10:46:01.662 DEBUG 15200 --- [ hystrix-name-1] demo.IUserService : [IUserService#getUserPage] ---> POST  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)
在日志中发现，header中没有被加上我之前设置的参数。说明该注解没有生效
于是debug调试
通过debug我发现feign会先将请求参数构建成Request对象，request信息如下：

从图中可看到，该Request实例的headers属性为空，而Request又是根据RequestTemplate模板对象生成的，RequestTemplate实例信息如下：
到这里可以看出，问题是出在RequestTemplate的构建构成中，于是我就去跟踪RequestTemplate构建的代码，发现RequestTemplate是根据MethodMetadata构建而成，而MethodMetadata就是对方法配置的抽象。
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);
      }
从上述代码可以看到，header的设置是由metadata的headerMapIndex 属性决定的，那么，设置headerMapIndex的位置，必然就和Header的解析相关，于是通过查看方法引用，我找到了下面的代码：
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()));
                }
            }
        }
    }
从代码中我们可以清晰的看到，解析过程中是从@RequestMapping或其派生注解的header属性中解析Header的，并且Header的key和value需要用“=”进行分割。
于是我修改成下面的形式，问题就解决了：
@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);
}
查看请求日志
2019-09-27 11:10:29.975 DEBUG 8604 --- [ hystrix-name-1] demo.IUserService : [IUserService#getUserPage] ---> POST  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)
请求中header已经被成功添加~
以上为个人经验，希望能给大家一个参考，也希望大家多多支持无名~