目录

• Feign调用服务Headers传参
• 我们可以使用RequestInterceptor来实现
• Feign设置Header头部,@Headers无效
• 于是开启feign的日志
• 于是debug调试

Feign调用服务Headers传参 在使用springcloud中经常会出现个服务调用，一般情况下会在Headers加上token的验证，那么在feign调用时候我们怎么去传这个token过去呢，有人会用@Headers这个注解来实现。但是这样方法太多笨重。

我们可以使用RequestInterceptor来实现
附上代码

import feign.RequestInterceptor; import feign.RequestTemplate; import org.springframework.stereotype.Component; import org.springframework.web.context.request.RequestContextHolder; import org.springframework.web.context.request.ServletRequestAttributes; import javax.servlet.http.HttpServletRequest; import java.util.Enumeration; @Componentpublic class SecuringRequestInterceptor implements RequestInterceptor {@Overridepublic void apply(RequestTemplate requestTemplate) {ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes(); HttpServletRequest request = attributes.getRequest(); Enumeration headerNames = request.getHeaderNames(); if (headerNames != null) {while (headerNames.hasMoreElements()) {String name = headerNames.nextElement(); String values = request.getHeader("Ttoken"); requestTemplate.header("Ttoken", values); }}}}

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 = "https://www.it610.com/article/getUserPage",method = RequestMethod.POST)@Headers(value=https://www.it610.com/article/{"ContentType=application/x-www-form-urlencoded","Inner_token=PXH0dP5I8qQ8UbFPpzm67cQkm7j8tWT2Kwn6J6SXYkfp2kMo/lSqHQ=="})public Map 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

@Configurationpublic class FeignConfig { @BeanLogger.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 = "https://www.it610.com/article/getUserPage",method = RequestMethod.POST)@Headers(value=https://www.it610.com/article/{"ContentType=application/x-www-form-urlencoded","Inner_token=PXH0dP5I8qQ8UbFPpzm67cQkm7j8tWT2Kwn6J6SXYkfp2kMo/lSqHQ=="})public Map 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://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：

文章图片

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：
【关于Feign调用服务Headers传参问题】
文章图片

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 valuestemplate = 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 keyif (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 = "https://www.it610.com/article/getUserPage",method = RequestMethod.POST,headers = {"ContentType=application/x-www-form-urlencoded","Inner_token=PXH0dP5I8qQ8UbFPpzm67cQkm7j8tWT2Kwn6J6SXYkfp2kMo/lSqHQ=="})@Headers(value=https://www.it610.com/article/{"ContentType=application/x-www-form-urlencoded","Inner_token=PXH0dP5I8qQ8UbFPpzm67cQkm7j8tWT2Kwn6J6SXYkfp2kMo/lSqHQ=="})public Map 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://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)

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脚本之家。

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