RequestInterceptor接口位于包io.github.openfeign-core下，使用Spring Cloud Feign的时候会自动依赖这个包

下面的代码会在每次调用Feign1的m1方法时，向HTTP头追加键值对武汉3:晴川历历汉阳树

@FeignClient(value = "feignA", url = "XXX或者el表达式${abc:默认值}")
public interface Feign1 {@GetMapping(value = "/api/xxx", headers = {"武汉1=杨泗港长江大桥","武汉2=鹦鹉洲长江大桥"})String m1();
}

package 你的包名;import feign.RequestInterceptor;
import feign.RequestTemplate;
import org.springframework.stereotype.Component;@Component
public class MyInterceptor implements RequestInterceptor {@Overridepublic void apply(RequestTemplate template) {String name = template.feignTarget().name();if ("feignA".equals(name)) {// 每次调用Feign1的m1方法时，都会往HTTP头追加武汉3=晴川历历汉阳树template.header("武汉3", "晴川历历汉阳树");}}
}