Ribbon&Feign

create()

updateListOfServers();

将接口bean替换为FactoryBeanspring 在getBean()阶段会调用FactoryBean的getObject()方法

获取feign 上下文FeignContext context = applicationContext.getBean(FeignContext.class);

会在spring的BeanDefinition注册阶段导入FeignClientsRegistrar bean定义@Import(FeignClientsRegistrar.class)

chooseServer

创建Feign上下文，在getObject创建动态代理阶段会从中获取FeignClient@Beanpublic FeignContext feignContext() {     FeignContext context = new FeignContext();    context.setConfigurations(this.configurations);    return context;}

executeAndDecode()

 return svc;

spring启动时创建rule(ZoneAvoidanceRule)rule.choose(key)

定时更新本地服务列表缓存enableAndInitLearnNewServersFeature();

枚举

Feign自动配置类FeignAutoConfiguration

build().newInstance(target);

Server server = loadBalancerContext.getServerFromLoadBalancer()

获取FactoryBean的beanDefinitionBeanDefinitionBuilder definition = BeanDefinitionBuilder.genericBeanDefinition(FeignClientFactoryBean.class);

向FactoryBean中设置@FeignClient注解上设置的属性值

invocationHandlerFactory

RibbonClientConfiguration配置中创建LoadBalancer到Spring容器

registerBeanDefinitions()自定义注册beanDefinition

 updateListOfServers();

@Bean@ConditionalOnMissingBeanpublic ILoadBalancer()

HystrixTargeter.target()

Targeter动态代理创建入口@Bean@ConditionalOnMissingBeanpublic Targeter feignTargeter() {    return new HystrixTargeter();}

目标方法动态代理，返回动态代理beangetTarget()

配置扫描器只扫描带有@FeignClient注解的接口scanner.addIncludeFilter(annotationTypeFilter);

注册下面类的BeanDefinitionFeignClientSpecification.class

 servers = serverListImpl.getUpdatedListOfServers();

build()

serverListUpdater.start(updateAction);

getObject()

获取扫描包路径basePackages = getBasePackages(metadata);

newInstance(target)

1

@EnableFeignClients

创建feign客服端默认配置属性类FeignClientProperties

registerClientConfiguration()

chooseRoundRobinAfterFiltering

Feign接口=getBean()FeignClientFactoryBean.class

创建FeignClient 建造者，其中会根据context中的配置，设置Feign。如：日志等级、编解码器、契约，配置属性文件中的配置等。Feign.Builder builder = feign(context);

使用openFeign需在启动类上加@EnableFeignClients，从该注解开始

从服务列表中选择服务ILoadBalancer lb = getLoadBalancer(); Server svc = lb.chooseServer(loadBalancerKey);

添加配置builder.addConstructorArgValue(configuration);

扫描出带有@FeignClient注解的接口的beanDefinitionSet<BeanDefinition> candidateComponents = scanner.findCandidateComponents(basePackage);

lbClient(clientName)

创建Http连接默认配置属性类FeignHttpClientProperties

导入Gzip 解密器，默认未开启，开启需要配置，且不能用okhttp3连接@Import(DefaultGzipDecoderConfiguration.class)

Runnable wrapperRunnable = new Runnable()

loadBalance()

创建Feign客服端扫描器，可以扫描到标注有@FeignClient注解的接口ClassPathScanningCandidateComponentProvider scanner = getScanner();

invoke()

注册默认规范registry.registerBeanDefinition(name + \".\

call（Server server）

executeWithLoadBalancer

由于FeignClientsRegistrar继承ImportBeanDefinitionRegistrar，该类会在beanDefinition注册阶段实例化，并调用接口方法registerBeanDefinitions()拿到注册器，自定义注册beanDefinition

调用Feign接口ReflectiveFeign.FeignInvocationHandler.invoke()

注入所有FeignClient配置@Autowired(required = false)private List<FeignClientSpecification> configurations = new ArrayList<>();

handler

选择server策略，获取数组下标（第几个server）incrementAndGetModulo(eligible.size())

command.submit()

run()

执行构造方法

最后回调参数

  restOfInit(clientConfig);

selectServer()

SynchronousMethodHandler =  dispatch.get(method)返回类型dispatch.get(method).invoke(args)

 updateAction.doUpdate();

集成了nacos，这里会调用nacos的获取实例方法

配置开启feign.compression.response.enabled = truefeign.compression.response.useGzipDecoder = true

feign.target(target);

代理方法被调用时，进入ReflectiveFeign.FeignInvocationHandler.invoke()方法return proxy;

枚举扫描包路径，扫描路径下的Feign接口for (String basePackage : basePackages)

AnnotationTypeFilter annotationTypeFilter = new AnnotationTypeFilter(FeignClient.class);