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Spring Cloud之Feign

  1. 依赖
  2. 自定义Http Client
    1. Apache Http Client
    2. OkHttp
  3. Client的扫描
  4. Feign接口仅支持继承一个接口
  5. 自定义feign超时

依赖

build.gradle
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implementation 'org.springframework.cloud:spring-cloud-starter-openfeign'

自定义Http Client

Apache Http Client

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implementation 'io.github.openfeign:feign-httpclient'

OkHttp

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implementation 'io.github.openfeign:feign-okhttp'

Client的扫描

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@EnableFeignClients(basePackageClasses = {
        Application.class, // 本项目根路径
        OtherClient.class  // 其他包的Client
})
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

注意：使用@ComponentScan无效

Feign接口仅支持继承一个接口

Contract.parseAndValidateMetadata

自定义feign超时

全局默认

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feign.client.config.default.connect-timeout=10000
feign.client.config.default.read-timeout=60000

指定FeignClient的配置

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feign.client.config.myContextId.connect-timeout=10000
feign.client.config.myContextId.read-timeout=60000

Spring构造Feign Client流程

org.springframework.cloud.openfeign.FeignClientFactoryBean#configureFeign

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protected void configureFeign(FeignContext context, Feign.Builder builder) {
    FeignClientProperties properties = beanFactory != null ? beanFactory.getBean(FeignClientProperties.class)
            : applicationContext.getBean(FeignClientProperties.class);

    FeignClientConfigurer feignClientConfigurer = getOptional(context, FeignClientConfigurer.class);
    setInheritParentContext(feignClientConfigurer.inheritParentConfiguration());

    if (properties != null && inheritParentContext) {
        if (properties.isDefaultToProperties()) {
            configureUsingConfiguration(context, builder);
            configureUsingProperties(properties.getConfig().get(properties.getDefaultConfig()), builder);
            configureUsingProperties(properties.getConfig().get(contextId), builder);
        }
        else {
            configureUsingProperties(properties.getConfig().get(properties.getDefaultConfig()), builder);
            configureUsingProperties(properties.getConfig().get(contextId), builder);
            configureUsingConfiguration(context, builder);
        }
    }
    else {
        configureUsingConfiguration(context, builder);
    }
}
  技术 / Java
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