SpringCloud gateway调用openFeign抛出@org.springframework.beans.factory.annotation.Autowired(required=t

问题描述

网关层进行统一鉴权和认证的过程中，需要远程调用鉴权服务器的接口进行鉴权的操作。但是在采用 OpenFiegn 进行远程调用的过程中，出现了如下的报错堆栈，导致了远程调用失败

堆栈信息

feign.codec.EncodeException: No qualifying bean of type 'org.springframework.boot.autoconfigure.http.HttpMessageConverters' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
	at feign.ReflectiveFeign$BuildEncodedTemplateFromArgs.resolve(ReflectiveFeign.java:384)
	Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
Error has been observed at the following site(s):
	|_ checkpoint ⇢ org.springframework.security.web.server.authorization.AuthorizationWebFilter [DefaultWebFilterChain]
	|_ checkpoint ⇢ org.springframework.security.web.server.authorization.ExceptionTranslationWebFilter [DefaultWebFilterChain]
	|_ checkpoint ⇢ org.sprin

关键信息

No qualifying bean of type 'org.springframework.boot.autoconfigure.http.HttpMessageConverters

解决方案

堆栈分析：HttpMessageConverters 没有被注入到容器中管理
1、源码：HttpMessageConverters.java 中没有发现异常，于是开始查看是否存在 AutoConfiguration 打开 HttpMessageConvertersAutoConfiguration.java

@Configuration(proxyBeanMethods = false)
@ConditionalOnClass(HttpMessageConverter.class)
@Conditional(NotReactiveWebApplicationCondition.class)
@AutoConfigureAfter({ GsonAutoConfiguration.class, JacksonAutoConfiguration.class, JsonbAutoConfiguration.class })
@Import({ JacksonHttpMessageConvertersConfiguration.class, GsonHttpMessageConvertersConfiguration.class,
		JsonbHttpMessageConvertersConfiguration.class })
public class HttpMessageConvertersAutoConfiguration {
}

2、源码：@Conditional(NotReactiveWebApplicationCondition.class) @Conditional 是 Spring4 新提供的注解，它的作用是按照一定的条件进行判断，满足条件给容器注册 bean 再查看类 NotReactiveWebApplicationCondition

static class NotReactiveWebApplicationCondition extends NoneNestedConditions {

		NotReactiveWebApplicationCondition() {
			super(ConfigurationPhase.PARSE_CONFIGURATION);
		}

		@ConditionalOnWebApplication(type = Type.REACTIVE)
		private static class ReactiveWebApplication {

		}

	}

3、Spring Cloud Gateway 是基于 WebFlux 的，是 ReactiveWeb，所以 HttpMessageConverters 不会自动注入。于是自己在配置文件中，直接复制源码的 Bean，最终成功。

# 新建配置类
@Configuration
public class WebFluxWithOpenFeignConfig {
    @Bean
    @ConditionalOnMissingBean
    public HttpMessageConverters messageConverters(ObjectProvider<HttpMessageConverter<?>> converters) {
        return new HttpMessageConverters(converters.orderedStream().collect(Collectors.toList()));
    }
}