spring初始化时会为每个声明的feignclient注册factorybean豆子，然后通过factorybean来生产feignclient豆子，所以现在关注点来到了FeignClientFactoryBean

可以看到它实现了3个接口，factorybean接口声明这是一个factorybean；InitializngBean接口用来在该豆子初始化结束时嵌入自定义逻辑，和@PostConstruct注解的功能一样；ApplicationContextAware接口顾名思义，实现该接口的类能够意识到ApplicationContext的存在。

feignclient的豆子是从FeignClientFactoryBean的getObject（）方法生产的

/**
 * @param <T> the target type of the Feign client
 * @return a {@link Feign} client created with the specified data and the context
 * information
 */
<T> T getTarget() {
   FeignContext context = this.applicationContext.getBean(FeignContext.class);
   Feign.Builder builder = feign(context);

   if (!StringUtils.hasText(this.url)) {
      if (!this.name.startsWith("http")) {
         this.url = "http://" + this.name;
      }
      else {
         this.url = this.name;
      }
      this.url += cleanPath();
      return (T) loadBalance(builder, context,
            new HardCodedTarget<>(this.type, this.name, this.url));
   }
   if (StringUtils.hasText(this.url) && !this.url.startsWith("http")) {
      this.url = "http://" + this.url;
   }
   String url = this.url + cleanPath();
   Client client = getOptional(context, Client.class);
   if (client != null) {
      if (client instanceof LoadBalancerFeignClient) {
         // not load balancing because we have a url,
         // but ribbon is on the classpath, so unwrap
         client = ((LoadBalancerFeignClient) client).getDelegate();
      }
      builder.client(client);
   }
   Targeter targeter = get(context, Targeter.class);
   return (T) targeter.target(this, builder, context,
         new HardCodedTarget<>(this.type, this.name, url));
}
可以看到，第一句就是获取FeignContext这个豆子，然而这个豆子是什么时候注册的呢？显然之前忽略了某个地方，这个地方就是FeignAutoConfiguration---spring boot的自动配置类。在spring.factories文件中指定了该类为自动配置类

 可以看到在这里注册了FeignContext豆子。现在暂时关注点移到FeignContext中，待会再回来。

FeignContext是什么呢？

//TODO