Spring Cloud Feign--统一设置Header--方法/

简介

        本文介绍Feign如何统一设置Header。

方法概述

        方法是：实现RequestInterceptor接口，将它作为配置类。

        如果这个实现类注入到Spring容器的话就会全局有效，即使在没有指定configuration属性的FeignClient也会使用该配置。

        如果只想给指定FeignClient的feign接口使用该配置，不要将该类配置注入Spring中，需要进行手动指定（假设实现类名为：TestFeignIntercepter）：

1.  
   @FeignClient(name = "user", configuration = {TestRequestInterceptor.class})
2.  
   public interface UserFeignClient {
3.  
   @GetMapping(value = "/user/{id}")
4.  
   public User findById(@RequestParam("id") String id);
5.  
   }

简单示例

1.  
   public class TestFeignInterceptor implements RequestInterceptor {
2.  
   @Override
3.  
   public void apply(RequestTemplate requestTemplate) {
4.  
   String url = requestTemplate.url();
5.  
   // 只对特定url进行签名添加Header的操作
6.  
   if (!url.startsWith("/test/api")) {
7.  
   return;
8.  
   }
9.  
    
10.  
    requestTemplate.header("Authorization", "xxx");
11.  
    }
12.  
    }

项目实例

实例1：转发Controller的所有header

1.  
   import feign.RequestInterceptor;
2.  
   import feign.RequestTemplate;
3.  
   import java.util.Enumeration;
4.  
   import javax.servlet.http.HttpServletRequest;
5.  
   import org.slf4j.Logger;
6.  
   import org.slf4j.LoggerFactory;
7.  
   import org.springframework.web.context.request.RequestAttributes;
8.  
   import org.springframework.web.context.request.RequestContextHolder;
9.  
   import org.springframework.web.context.request.ServletRequestAttributes;
10.  
     
11.  
    public class FeignTransmitAllHeaderInterceptor implements RequestInterceptor {
12.  
     
13.  
    @Override
14.  
    public void apply(RequestTemplate template) {
15.  
    ServletRequestAttributes attributes = (ServletRequestAttributes)
16.  
    RequestContextHolder.getRequestAttributes();
17.  
    HttpServletRequest request = attributes.getRequest();
18.  
    Enumeration<String> headerNames = request.getHeaderNames();
19.  
    if (headerNames != null) {
20.  
    while (headerNames.hasMoreElements()) {
21.  
    String name = headerNames.nextElement();
22.  
    String values = request.getHeader(name);
23.  
    template.header(name, values);
24.  
    }
25.  
    }
26.  
    }
27.  
    }

实例2：转发Controller的header（修改部分header）

1.  
   import feign.RequestInterceptor;
2.  
   import feign.RequestTemplate;
3.  
   import java.util.Enumeration;
4.  
   import javax.servlet.http.HttpServletRequest;
5.  
   import org.slf4j.Logger;
6.  
   import org.slf4j.LoggerFactory;
7.  
   import org.springframework.web.context.request.RequestAttributes;
8.  
   import org.springframework.web.context.request.RequestContextHolder;
9.  
   import org.springframework.web.context.request.ServletRequestAttributes;
10.  
     
11.  
    public class FeignTransmitAllHeaderInterceptor implements RequestInterceptor {
12.  
     
13.  
    @Override
14.  
    public void apply(RequestTemplate requestTemplate) {
15.  
    RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
16.  
    if (requestAttributes != null) {
17.  
    ServletRequestAttributes attributes = (ServletRequestAttributes)requestAttributes;
18.  
    HttpServletRequest request = attributes.getRequest();
19.  
    Enumeration<String> headerNames = request.getHeaderNames();
20.  
    if (headerNames != null) {
21.  
    while(headerNames.hasMoreElements()) {
22.  
    String headerName; = (String)headerNames.nextElement();
23.  
    String headerValue = request.getHeader(headerName);
24.  
    if (!headerName.equals("content-length")) {
25.  
    requestTemplate.header(headerName, headerValue);
26.  
    }
27.  
    }
28.  
     
29.  
    String path = request.getContextPath();
30.  
    String modifiedReferer = request.getScheme() "://" request.getServerName()
31.  
    ":" request.getServerPort() path request.getServletPath();
32.  
    requestTemplate.header("referer", modifiedReferer);
33.  
    }
34.  
    }
35.  
    }
36.  
    }

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