Feign异常--A bean with that name | HTTP method type (ex. GET, POST)

心已赠人 2023-01-16 12:28 94阅读 0赞

### 文章目录 ###

*  1、前置
 *  2、重现异常A:
 *  3、重现异常B:
 *  4、分析问题
 *  5、解决方法
 *  6、完结

--------------------

# 1、前置 #

1、这里是两个异常(别名as)  
第一个异常 ‘as’ A: A bean with that name has already been defined and overriding is disabled.  
第二个 ‘as’ B: Method GetFeignClient\#getParameters(String,String) not annotated with HTTP method type (ex. GET, POST)  
2、看了一下网上给的解决方案, 但是并没有详细的说明, 本篇文章会进行详细的解释  
3、版本: Spring Cloud: Hoxton.SR3、spring-cloud-openfeign: 2.2.2.RELEASE

# 2、重现异常A: #

@FeignClient(name = "provider")
    public interface GetFeignClient { 
    	@RequestMapping(value = "/getNoParameters", method = RequestMethod.GET)
        CommonResult getNoParameters();
    }
    
    @FeignClient(name = "provider")
    public interface PostFeignClient { 
    	@RequestMapping(value = "/testPost/postNoParameters", method = RequestMethod.POST)
        CommonResult postNoParameters();
    }

启动项目报错: The bean ‘provider.FeignClientSpecification’ could not be registered. A bean with that name has already been defined and overriding is disabled.  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM4NjM3NTU4_size_16_color_FFFFFF_t_70]

# 3、重现异常B: #

在重现异常B之前, 我们要先将异常A给解决掉, 就用最快捷的方式进行解决:(强烈不推荐该方式, 后面会说)

spring:
      main:
        allow-bean-definition-overriding: true

@FeignClient(name = "provider")
    public interface GetFeignClient { 
    	@RequestMapping(value = "/getNoParameters", method = RequestMethod.GET)
        CommonResult getNoParameters();
    }
    
    @FeignClient(name = "provider", configuration = FooConfiguration.class)
    public interface HeaderFeignClient { 
      	@RequestLine("GET /testHeard/getHeard")
        CommonResult getHeard(@SpringQueryMap TestEntity data, @HeaderMap Map<String, Object> headerMap);
    }

FooConfiguration:

package com.chaim.feignserver.config;
    
    import feign.Contract;
    import org.springframework.context.annotation.Bean;
    
    /** * 详情说明见 Readme.md * 可以参考代码地址 * * @author Chaim * @date 2021/4/19 10:59 */
    //@Configurable
    public class FooConfiguration { 
    
        /** * 将契约改为 feign 原生的默认契约. * 可以使用feign自带的注解 * * @return */
        @Bean
        public Contract feignContract() { 
            return new feign.Contract.Default();
        }

关于FooConfiguration 说明:

@Configurable
    
    feign 配置  
    在 SpringCloud 中，Feign 的默认配置类是 FeignClientsConfiguration, 该类定义了 feign 默认使用的编码器、解码器、所使用的契约等.  
    SpringCloud允许通过注解@FeignClient的configuration属性自定义Feign的配置 (@FeignClient(configuration= FooConfiguration.class)),  
    自定义配置的优先级比FeighClientsConfiguration要高.  
    
    可以使用 @Configurable, 声明这是一个配置类, 但此时不能将该放置在主应用程序上下文 @ComponentScan 所扫描的包中, 否则该配置将会被所有Feign Client共享，无法实现细粒度配置！  
    反之, 也可以不使用 @Configurable, 从而避免父子上下文问题  
    
    官网中有介绍(1.2): https://docs.spring.io/spring-cloud-openfeign/docs/2.2.x-SNAPSHOT/reference/html/index.html  
    摘抄:   
    FooConfiguration does not need to be annotated with @Configuration. However, if it is, then take care to exclude it from any @ComponentScan that would otherwise include this configuration as it will become the default source for feign.Decoder, feign.Encoder, feign.Contract, etc., when specified. This can be avoided by putting it in a separate, non-overlapping package from any @ComponentScan or @SpringBootApplication, or it can be explicitly excluded in @ComponentScan.

启动项目报错: FactoryBean threw exception on object creation; nested exception is java.lang.IllegalStateException: Method GetFeignClient\#getParameters(String,String) not annotated with HTTP method type (ex. GET, POST)  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM4NjM3NTU4_size_16_color_FFFFFF_t_70 1]

# 4、分析问题 #

异常A: bean名称相同, 重复的bean被定义了, 这个就不多说了  
  
异常B: 这个就有点意思了, 他也是基于bean名称重复定义导致产生的, 简单的深入一下  
1、HeaderFeignClient 指定了原生契约, 他的bean名字是provider,  
2、GetFeignClient 未指定原生契约, 他的bean名字也是provider,  
3、而@RequestMapping并不属于原生契约, 也就是说原生契约下不支持该注解, 就会报该error  
4、那么当spring注入名称:provider引用原生契约对应的注解, 该provider都只能使用原生契约支持的注解  
测试一下我们的说法:

@FeignClient(name = "provider", configuration = FooConfiguration.class)
    public interface HeaderFeignClient extends HeaderService { 
        @RequestLine("GET /testHeard/getHeard")
        CommonResult getHeard(@SpringQueryMap TestEntity data, @HeaderMap Map<String, Object> headerMap);
    
        @RequestMapping(value = "/getNoParameters", method = RequestMethod.GET)
        CommonResult getNoParameters();
    }

启动项目依旧报错, 那么就验证了我们上面说的流程

# 5、解决方法 #

1、指定: contextId: 用作bean名，但不会作为服务id

@FeignClient(name = "provider", contextId = "headerProvider", configuration = FooConfiguration.class)
    public interface HeaderFeignClient { 
        @RequestLine("GET /testHeard/getHeard")
        CommonResult getHeard(@SpringQueryMap TestEntity data, @HeaderMap Map<String, Object> headerMap);
    }

2、开启了原生契约支持, 那么就只能使用原生契约支持的注解, 不能混用  
3、不到万不得已的情况下**不要用spring.main.allow-bean-definition-overriding=true**用我们话说就是捏到鼻子哄眼睛

# 6、完结 #

1、简单说该问题, 如果使用@RequestLine等原生契约支持的注解, 那么就要通过configuration 配置原生契约, 并且只能使用原生契约支持的注解

2、openfeign对应的其余文章:

[代码地址以及对应的postman文件][postman]  
[Feign的使用示列–呕心沥血之作(1)][Feign_1]  
[Feign的@FeignClient详解–呕心沥血之作(2)][Feign_FeignClient_2]  
[Feign的默认契约注解详解–呕心沥血之作(3)][Feign_3]  
[Feign异常–Request method ‘POST‘ not supported][Feign_Request method _POST_ not supported]  
[Feign异常–A bean with that name | HTTP method type (ex. GET, POST)][Feign_A bean with that name _ HTTP method type _ex. GET_ POST]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM4NjM3NTU4_size_16_color_FFFFFF_t_70]: /images/20221022/8c8054d5308d44dc8e2a5e84d46018f4.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM4NjM3NTU4_size_16_color_FFFFFF_t_70 1]: /images/20221022/02d60dd772734ccab880afb9ac7fa0fa.png
[postman]: https://gitee.com/xmaxm/test-code
[Feign_1]: https://blog.csdn.net/qq_38637558/article/details/115866969
[Feign_FeignClient_2]: https://blog.csdn.net/qq_38637558/article/details/116130453
[Feign_3]: https://blog.csdn.net/qq_38637558/article/details/116140950
[Feign_Request method _POST_ not supported]: https://blog.csdn.net/qq_38637558/article/details/115913345
[Feign_A bean with that name _ HTTP method type _ex. GET_ POST]: https://blog.csdn.net/qq_38637558/article/details/116141025