详解Spring Cloud Feign 熔断配置的一些小坑
1.在使用feign做服务调用时,使用继承的方式调用服务,加入Hystrix的熔断处理fallback配置时,会报错,已解决。2.使用feign默认配置,熔断不生效,已解决。
最近在做微服务的学习,发现在使用feign做服务调用时,使用继承的方式调用服务,加入Hystrix的熔断处理fallback配置时,会报错,代码如下:
@RequestMapping("/demo/api") publicinterfaceHelloApi{ @GetMapping("user/{id}") UsergetUserById(@PathVariable("id")longid); @GetMapping("hello") Stringecho(@RequestParam("name")Stringname); }
@FeignClient(value="ms-server",fallback=ConsumerFeignServiceFallBack.class) publicinterfaceConsumerFeignServiceextendsHelloApi{ }
@Component publicclassConsumerFeignServiceFallBackimplementsConsumerFeignService{ @Override publicUsergetUserById(longid){ returnnewUser(); } @Override publicStringecho(Stringname){ return"echoerror:"+name; } }
报错如下:
Causedby:java.lang.IllegalStateException:Ambiguousmapping.Cannotmap'com.thoughtworks.demo.consumer.service.ConsumerFeignService'method
publicabstractjava.lang.Stringcom.thoughtworks.demo.api.HelloApi.echo(java.lang.String)
to{[/demo/api/hello],methods=[GET]}:Thereisalready'consumerFeignServiceFallBack'beanmethod
publicjava.lang.Stringcom.thoughtworks.demo.consumer.service.ConsumerFeignServiceFallBack.echo(java.lang.String)mapped.
atorg.springframework.web.servlet.handler.AbstractHandlerMethodMapping$MappingRegistry.assertUniqueMethodMapping(AbstractHandlerMethodMapping.java:576)~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
atorg.springframework.web.servlet.handler.AbstractHandlerMethodMapping$MappingRegistry.register(AbstractHandlerMethodMapping.java:540)~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
atorg.springframework.web.servlet.handler.AbstractHandlerMethodMapping.registerHandlerMethod(AbstractHandlerMethodMapping.java:264)~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
atorg.springframework.web.servlet.handler.AbstractHandlerMethodMapping.detectHandlerMethods(AbstractHandlerMethodMapping.java:250)~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
atorg.springframework.web.servlet.handler.AbstractHandlerMethodMapping.initHandlerMethods(AbstractHandlerMethodMapping.java:214)~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
atorg.springframework.web.servlet.handler.AbstractHandlerMethodMapping.afterPropertiesSet(AbstractHandlerMethodMapping.java:184)~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
atorg.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping.afterPropertiesSet(RequestMappingHandlerMapping.java:127)~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
atorg.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1687)~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
atorg.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1624)~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
...21commonframesomitted
错误原因是这里继承的接口类是一个controller接口,继承时会继承到父类的
@RequestMapping("/demo/api")
SpringMvc在做mapping映射的时候发现ConsumerFeignService和ConsumerFeignServiceFallBack的mapping重复了,所以抛出异常,如何解决呢?
解决的方法有2个:
一是更改ConsumerFeignServiceFallBack的mapping配置,代码如下:
@Component @RequestMapping("fallback/demo/api") publicclassConsumerFeignServiceFallBackimplementsConsumerFeignService{ @Override publicUsergetUserById(longid){ returnnewUser(); } @Override publicStringecho(Stringname){ return"echoerror:"+name; } }
二是使用fallbackFactory,代码如下:
@Component publicclassConsumerFeignServiceFallBackimplementsFallbackFactory{ @Override publicConsumerFeignServicecreate(Throwablecause){ returnnewConsumerFeignService(){ @Override publicUsergetUserById(longid){ returnnewUser(); } @Override publicStringecho(Stringname){ return"echoerror:"+name; } }; } }
运行后,关闭服务提供者,发现熔断并没有生效,没有像单独使用@HystrixCommand时进入fallback方法,查了很多方式,发现原来是feign的hystix的配置开关没有打开
解决方法,在application.yml中增加配置如下:
feign: hystrix: enabled:true
在IntelliJIDEA里也没有这个配置的提示,还报告警告,不知道算不算是个BUG,这里我使用的版本是
springBootVersion='1.5.10.RELEASE' springCloudVersion='Edgware.SR3'
以上就是我在使用feign时发现的一些小坑,希望对大家的学习有所帮助,也希望大家多多支持毛票票。