详谈Feign的配置类是如何生效的

目录

• 1. Feign
• 1.1 配置类：ApiConfiguration.java
• 1.2 FeignClientsRegistrar
• 1.3 FeignAutoConfiguration
• 1.4 FeignClientFactoryBean的定义
• 1.5 FeignClientsConfiguration
• 1.6 FeignClientProperties
• 1.7 再看FeignClientFactoryBean
• 1.8 FeignRibbonClientAutoConfiguration
• 1.9 LoadBalancerFeignClient
• 2.0 FeignLoadBalancer

说明，该源码部分只是个人总结，随手记录，不保证正确性；

该源码关注的不是底层Feign是如何完成远程调用的具体细节，而关注在Feign在完成远程调用之前的准备工作，他的一些配置是如何生效的；看完之后对Spring的ImportBeanDefinitionRegistrar接口比之前的理解更加深了，而且想玩自定义注解提供扩展功能的，熟悉了Feign的几个流程之后还是能够提供很大的指导意见的；

1. Feign

特别说明一下，是在使用了Ribbon的基础上加入了Feign的研读，不确定Ribbon是否会对Feign有影响

1.1 配置类：ApiConfiguration.java

@Configuration
@EnableAspectJAutoProxy
@EnableFeignClients(basePackages = "com.sinotrans.hd.microservice.api.feign")
public class ApiConfiguration {
}

重点来看一下@EnableFeignClients做了哪些事情，除了该注解本身提供的属性配置外，可以看到还导入了一个配置类FeignClientsRegistrar

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
@Documented
@Import(FeignClientsRegistrar.class)
public @interface EnableFeignClients {
}

1.2 FeignClientsRegistrar

现在来看一下FeignClientsRegistrar做了什么事情，该类实现了Spring的众多接口，ImportBeanDefinitionRegistrar接口，简单点说该接口提供了可以给容器动态注入Bean的功能，ResourceLoaderAware可以获得容器资源依赖，BeanClassLoaderAware提供Bean的回调功能，EnvironmentAware获得当前应用的环境变量信息

class FeignClientsRegistrar implements ImportBeanDefinitionRegistrar,
  ResourceLoaderAware, BeanClassLoaderAware, EnvironmentAware {
    @Override
    public void registerBeanDefinitions(AnnotationMetadata metadata,
            BeanDefinitionRegistry registry) {
        registerDefaultConfiguration(metadata, registry);
        registerFeignClients(metadata, registry);
    }
｝

先看一下第一个方法registerDefaultConfiguration(),代码如下,

    private void registerDefaultConfiguration(AnnotationMetadata metadata,
            BeanDefinitionRegistry registry) {
        Map<String, Object> defaultAttrs = metadata
                .getAnnotationAttributes(EnableFeignClients.class.getName(), true);
        if (defaultAttrs != null && defaultAttrs.containsKey("defaultConfiguration")) {
            String name;
            if (metadata.hasEnclosingClass()) {
                name = "default." + metadata.getEnclosingClassName();
            }
            else {
                name = "default." + metadata.getClassName();
            }
            registerClientConfiguration(registry, name,
                    defaultAttrs.get("defaultConfiguration"));
        }
    }

defaultAttrs，先获得当前配置类的注解@EnableFeignClients类的全部属性，目前能够获取到在前面配置的属性basePackages = "com.sinotrans.hd.microservice.api.feign",再往下判断属性是否为空，是否包含defaultConfiguration，程序往下走，目前属性不为空且包含defaultConfiguration，hasEnclosingClass()判断当前注解类是否是内部类，如果是内部类，则使用default. + 顶级类名，否则使用default. + 自己的类名，当前name=default.com.sinotrans.hd.microservice.api.config.ApiConfiguration

registerClientConfiguration()方法，内部代码如下

    private void registerClientConfiguration(BeanDefinitionRegistry registry, Object name, Object configuration) {
        BeanDefinitionBuilder builder = BeanDefinitionBuilder
                .genericBeanDefinition(FeignClientSpecification.class);
        builder.addConstructorArgValue(name);
        builder.addConstructorArgValue(configuration);
        registry.registerBeanDefinition(
                name + "." + FeignClientSpecification.class.getSimpleName(),
                builder.getBeanDefinition());
    }

第一行首先预定义一个org.springframework.cloud.netflix.feign.FeignClientSpecification类型的Bean信息，通过构造方法设置FeignClientSpecification的name和configuration类，结合上面name属性的设置，定义的这个Bean的名称为default.com.sinotrans.hd.microservice.api.config.ApiConfiguration.FeignClientSpecification，调用FeignClientSpecification的构造方法来初始化这个类

FeignClientSpecification.java

class FeignClientSpecification implements NamedContextFactory.Specification {
    public FeignClientSpecification(String name, Class<?>[] configuration) {
        this.name = name;
        this.configuration = configuration;
    }
}

现在来看一下registerFeignClients(metadata, registry);方法源码如下：

    public void registerFeignClients(AnnotationMetadata metadata,
            BeanDefinitionRegistry registry) {
        ClassPathScanningCandidateComponentProvider scanner = getScanner();
        scanner.setResourceLoader(this.resourceLoader);
        Set<String> basePackages;
        Map<String, Object> attrs = metadata
                .getAnnotationAttributes(EnableFeignClients.class.getName());
        AnnotationTypeFilter annotationTypeFilter = new AnnotationTypeFilter(
                FeignClient.class);
        final Class<?>[] clients = attrs == null ? null
                : (Class<?>[]) attrs.get("clients");
        if (clients == null || clients.length == 0) {
            scanner.addIncludeFilter(annotationTypeFilter);
            basePackages = getBasePackages(metadata);
        }
        else {
            final Set<String> clientClasses = new HashSet<>();
            basePackages = new HashSet<>();
            for (Class<?> clazz : clients) {
                basePackages.add(ClassUtils.getPackageName(clazz));
                clientClasses.add(clazz.getCanonicalName());
            }
            AbstractClassTestingTypeFilter filter = new AbstractClassTestingTypeFilter() {
                @Override
                protected boolean match(ClassMetadata metadata) {
                    String cleaned = metadata.getClassName().replaceAll("\\$", ".");
                    return clientClasses.contains(cleaned);
                }
            };
            scanner.addIncludeFilter(
                    new AllTypeFilter(Arrays.asList(filter, annotationTypeFilter)));
        }
        for (String basePackage : basePackages) {
            Set<BeanDefinition> candidateComponents = scanner
                    .findCandidateComponents(basePackage);
            for (BeanDefinition candidateComponent : candidateComponents) {
                if (candidateComponent instanceof AnnotatedBeanDefinition) {
                    // verify annotated class is an interface
                    AnnotatedBeanDefinition beanDefinition = (AnnotatedBeanDefinition) candidateComponent;
                    AnnotationMetadata annotationMetadata = beanDefinition.getMetadata();
                    Assert.isTrue(annotationMetadata.isInterface(),
                            "@FeignClient can only be specified on an interface");
                    Map<String, Object> attributes = annotationMetadata
                            .getAnnotationAttributes(
                                    FeignClient.class.getCanonicalName());
                    String name = getClientName(attributes);
                    registerClientConfiguration(registry, name,
                            attributes.get("configuration"));
                    registerFeignClient(registry, annotationMetadata, attributes);
                }
            }
        }
    }

① 这个方法的代码有点长，首先获得包扫描类，获得系统资源加载类，然后获得配置类的@EnableFeignClients注解的所有属性，定义一个匹配FeignClient的过滤器，clients属性，则是判断当前@EnableFeignClients是否有配置过clients属性，该属性的作用是明确指定标注了@FeignClient注解的接口类，如果配置了这个属性，则类路径扫描会被禁用，则basePackages扫描包路径的值会将clients属性的接口类所在的包加入扫描路径，否则使用类路径扫描。当前使用类路径扫描；clients的值一旦为空或长度为0，那么则包扫描规则加入一个includeFilters规则为只扫描带@FeignClient注解的类,packageSearchPath=classpath*:com/sinotrans/hd/microservice/api/feign/**/*.class

② findCandidateComponents()方法循环包扫描路径，查找指定包路径下符合条件的class，然后作为BeanDefinition集合返回，代码如下

    /**
     * Scan the class path for candidate components.
     * @param basePackage the package to check for annotated classes
     * @return a corresponding Set of autodetected bean definitions
     */
    public Set<BeanDefinition> findCandidateComponents(String basePackage) {
        Set<BeanDefinition> candidates = new LinkedHashSet<BeanDefinition>();
        try {
            String packageSearchPath = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX +
                    resolveBasePackage(basePackage) + '/' + this.resourcePattern;
            Resource[] resources = this.resourcePatternResolver.getResources(packageSearchPath);
            boolean traceEnabled = logger.isTraceEnabled();
            boolean debugEnabled = logger.isDebugEnabled();
            for (Resource resource : resources) {
                if (traceEnabled) {
                    logger.trace("Scanning " + resource);
                }
                if (resource.isReadable()) {
                    try {
                        MetadataReader metadataReader = this.metadataReaderFactory.getMetadataReader(resource);
                        if (isCandidateComponent(metadataReader)) {
                            ScannedGenericBeanDefinition sbd = new ScannedGenericBeanDefinition(metadataReader);
                            sbd.setResource(resource);
                            sbd.setSource(resource);
                            if (isCandidateComponent(sbd)) {
                                if (debugEnabled) {
                                    logger.debug("Identified candidate component class: " + resource);
                                }
                                candidates.add(sbd);
                            }
                            else {
                                if (debugEnabled) {
                                    logger.debug("Ignored because not a concrete top-level class: " + resource);
                                }
                            }
                        }
                        else {
                            if (traceEnabled) {
                                logger.trace("Ignored because not matching any filter: " + resource);
                            }
                        }
                    }
                    catch (Throwable ex) {
                        throw new BeanDefinitionStoreException(
                                "Failed to read candidate component class: " + resource, ex);
                    }
                }
                else {
                    if (traceEnabled) {
                        logger.trace("Ignored because not readable: " + resource);
                    }
                }
            }
        }
        catch (IOException ex) {
            throw new BeanDefinitionStoreException("I/O failure during classpath scanning", ex);
        }
        return candidates;
    }

③ 循环返回的candidateComponents，而且类型必须为AnnotatedBeanDefinition并且必须是接口，然后获得该接口上的@FeignClient注解的属性，包含服务名，和请求上下文（包含上下文和控制层的RequestMapping），内容如下

④ 通过方法getClientName()获取服务名，可以看到服务名的规则是value > name > serviceId依次去取，直到取不到抛出异常

   private String getClientName(Map<String, Object> client) {
        if (client == null) {
            return null;
        }
        String value = (String) client.get("value");
        if (!StringUtils.hasText(value)) {
            value = (String) client.get("name");
        }
        if (!StringUtils.hasText(value)) {
            value = (String) client.get("serviceId");
        }
        if (StringUtils.hasText(value)) {
            return value;
        }
        throw new IllegalStateException("Either 'name' or 'value' must be provided in @"
                + FeignClient.class.getSimpleName());
    }

⑤ registerClientConfiguration()方法将服务名注册成FeignClientSpecification类型的Bean放入预定义Bean容器，名称为服务名"." + FeignClientSpecification.class.getSimpleName()，同时也将服务名和配置类分别通过构造方法赋值给FeignClientSpecification的name和configuration属性，每个服务所需要引用的接口类有多个，所以这里可能会重复注册registerClientConfiguration，因为这里只是定义信息，所以应该是hi后来的会覆盖之前的吧。所以最终注入的应当是服务名去重后的数量，注入的时候也应当使用集合来接收注入，这个在后面会碰到；所以到了这里加上之前定义的默认的配置类生成的FeignClientSpecification，目前一共会有（）服务数 + 配置类默认生成的）个FeignClientSpecification

    private void registerClientConfiguration(BeanDefinitionRegistry registry, Object name,
            Object configuration) {
        BeanDefinitionBuilder builder = BeanDefinitionBuilder
                .genericBeanDefinition(FeignClientSpecification.class);
        builder.addConstructorArgValue(name);
        builder.addConstructorArgValue(configuration);
        registry.registerBeanDefinition(
                name + "." + FeignClientSpecification.class.getSimpleName(),
                builder.getBeanDefinition());
    }

⑥ registerFeignClient()方法，首先通过BeanDefinitionBuilder定义FeignClientFactoryBean类型的Bean，然后将@FeignClient里的所有属性都加入到BeanDefinitionBuilder的propertyValues里，通过这种方式给FeignClientFactoryBean的属性赋值，定义注入方式为AbstractBeanDefinition.AUTOWIRE_BY_TYPE，通过BeanDefinitionHolder对象将Bean的alias定义为服务名+“FeignClient”,beanName=类的全路径，注册beanName的alias，这一块存疑，每个接口不同，但服务相同，alias会相同，不知道这个alias的作用是什么？

FeignClientFactoryBean.java属性如下

class FeignClientFactoryBean implements FactoryBean<Object>, InitializingBean,
        ApplicationContextAware {
    /***********************************
     * WARNING! Nothing in this class should be @Autowired. It causes NPEs because of some lifecycle race condition.
     ***********************************/
    private Class<?> type;
    private String name;
    private String url;
    private String path;
    private boolean decode404;
    private ApplicationContext applicationContext;
    private Class<?> fallback = void.class;
    private Class<?> fallbackFactory = void.class;
}

private void registerFeignClient(BeanDefinitionRegistry registry,
            AnnotationMetadata annotationMetadata, Map<String, Object> attributes) {
        String className = annotationMetadata.getClassName();
        BeanDefinitionBuilder definition = BeanDefinitionBuilder
                .genericBeanDefinition(FeignClientFactoryBean.class);
        validate(attributes);
        definition.addPropertyValue("url", getUrl(attributes));
        definition.addPropertyValue("path", getPath(attributes));
        String name = getName(attributes);
        definition.addPropertyValue("name", name);
        definition.addPropertyValue("type", className);
        definition.addPropertyValue("decode404", attributes.get("decode404"));
        definition.addPropertyValue("fallback", attributes.get("fallback"));
        definition.addPropertyValue("fallbackFactory", attributes.get("fallbackFactory"));
        definition.setAutowireMode(AbstractBeanDefinition.AUTOWIRE_BY_TYPE);
        String alias = name + "FeignClient";
        AbstractBeanDefinition beanDefinition = definition.getBeanDefinition();
        boolean primary = (Boolean)attributes.get("primary"); // has a default, won't be null
        beanDefinition.setPrimary(primary);
        String qualifier = getQualifier(attributes);
        if (StringUtils.hasText(qualifier)) {
            alias = qualifier;
        }
        BeanDefinitionHolder holder = new BeanDefinitionHolder(beanDefinition, className,
                new String[] { alias });
        BeanDefinitionReaderUtils.registerBeanDefinition(holder, registry);
    }

1.3 FeignAutoConfiguration

先看一下该类的定义，@ConditionalOnClass(Feign.class)一旦类路径下引入了Feign的包，则该配置类会自动生效，然后导入配置属性类信息

@Configuration
@ConditionalOnClass(Feign.class)
@EnableConfigurationProperties({FeignClientProperties.class, FeignHttpClientProperties.class})
public class FeignAutoConfiguration {
    @Autowired(required = false)
    private List<FeignClientSpecification> configurations = new ArrayList<>();

    @Bean
    public FeignContext feignContext() {
        FeignContext context = new FeignContext();
        context.setConfigurations(this.configurations);
        return context;
    }
｝

① 注入一个名为feignContext类型为FeignContext的bean,使用默认的配置类FeignClientsConfiguration通过父类NamedContextFactory来构建，，将所有feign相关的配置设置进去，包含了Feign的上下文信息，FeignClientsConfiguration通过实现ApplicationContextAware来注入ApplicationContext， 并将ApplicationContext作为FeignContext的父容器，关于FeignClientsConfiguration在后面章节讲述

FeignContext.java

    public FeignContext() {
        super(FeignClientsConfiguration.class, "feign", "feign.client.name");
    }

NamedContextFactory.java

/**
 * Creates a set of child contexts that allows a set of Specifications to define the beans
 * in each child context.
 *
 * Ported from spring-cloud-netflix FeignClientFactory and SpringClientFactory
 *
 * @author Spencer Gibb
 * @author Dave Syer
 */
public abstract class NamedContextFactory<C extends NamedContextFactory.Specification>
        implements DisposableBean, ApplicationContextAware {
    public interface Specification {
        String getName();
        Class<?>[] getConfiguration();
    }
    private Map<String, AnnotationConfigApplicationContext> contexts = new ConcurrentHashMap<>();
    private Map<String, C> configurations = new ConcurrentHashMap<>();
    private ApplicationContext parent;
    private Class<?> defaultConfigType;
    private final String propertySourceName;
    private final String propertyName;
    public NamedContextFactory(Class<?> defaultConfigType, String propertySourceName,
            String propertyName) {
        this.defaultConfigType = defaultConfigType;
        this.propertySourceName = propertySourceName;
        this.propertyName = propertyName;
    }

    public void setConfigurations(List<C> configurations) {
        for (C client : configurations) {
            this.configurations.put(client.getName(), client);
        }
    }
}

② FeignContext创建完成之后，下一步context.setConfigurations(this.configurations); 通过代码可以看到this.configurations指向的是本类的一个属性，通过@Autowired注入，然后我们看到注入的这个类型，FeignClientSpecification在前面我们看到了，这个是根据@FeignContext上的服务名来进行创建的类型，详见org.springframework.cloud.netflix.feign.FeignClientsRegistrar#registerClientConfiguration方法，所以在之前我们注入的FeignClientSpecification，也解决了之前的疑惑，既然会注入多个同类型的Bean，所以这里只能通过集合来接收注入，根据NamedContextFactory的源码可以看到它的configurations属性是一个ConcurrentHashMap,ConcurrentHashMap的key是FeignClientSpecification的name属性，关于name属性的值的规则前面也已经看到了， ConcurrentHashMap的value就是每个FeignClientSpecification对象本身

@Autowired(required = false)
private List<FeignClientSpecification> configurations = new ArrayList<>();

1.4 FeignClientFactoryBean的定义

该类部分源码如下：

实现了FactoryBean接口来完成Bean的注入，最终注入的对象通过getObject()方法返回，实现了

InitializingBean接口通过afterPropertiesSet()方法来检查name属性的赋值，实现了ApplicationContextAware接口来获得ApplicationContext容器，其中在前面也已经看到该类的属性赋值过程是如何实现的，这里不再细述。

class FeignClientFactoryBean implements FactoryBean<Object>, InitializingBean,
        ApplicationContextAware {
    /***********************************
     * WARNING! Nothing in this class should be @Autowired. It causes NPEs because of some lifecycle race condition.
     ***********************************/
    private Class<?> type;
    private String name;
    private String url;
    private String path;
    private boolean decode404;
    private ApplicationContext applicationContext;
    private Class<?> fallback = void.class;
    private Class<?> fallbackFactory = void.class;
    @Override
    public void afterPropertiesSet() throws Exception {
        Assert.hasText(this.name, "Name must be set");
    }
    @Override
    public void setApplicationContext(ApplicationContext context) throws BeansException {
        this.applicationContext = context;
    }

    @Override
    public Object getObject() throws Exception {
        FeignContext context = applicationContext.getBean(FeignContext.class);
        Feign.Builder builder = feign(context);
    }
｝

① 现在重点来看一下getObject()方法，首先从ApplicationContext容器中获得FeignContext对象，该对象在上一步已经看到如何注入的，下一步调用feign()方法，该方法代码如下

class FeignClientFactoryBean implements FactoryBean<Object>, InitializingBean,
        ApplicationContextAware {
    protected Feign.Builder feign(FeignContext context) {
        FeignLoggerFactory loggerFactory = get(context, FeignLoggerFactory.class);
        Logger logger = loggerFactory.create(this.type);
        // @formatter:off
        Feign.Builder builder = get(context, Feign.Builder.class)
                // required values
                .logger(logger)
                .encoder(get(context, Encoder.class))
                .decoder(get(context, Decoder.class))
                .contract(get(context, Contract.class));
        // @formatter:on
        configureFeign(context, builder);
        // 省略其它代码
    }

    protected <T> T get(FeignContext context, Class<T> type) {
        T instance = context.getInstance(this.name, type);
        if (instance == null) {
            throw new IllegalStateException("No bean found of type " + type + " for "
                    + this.name);
        }
        return instance;
    }

    protected void configureFeign(FeignContext context, Feign.Builder builder) {
        FeignClientProperties properties = applicationContext.getBean(FeignClientProperties.class);
        // 省略其它代码
    }
}

首先第一步FeignLoggerFactory loggerFactory = get(context, FeignLoggerFactory.class);点开get()方法，最终执行org.springframework.cloud.context.named.NamedContextFactory#createContext，传入的name即FeignClientFactoryBean的name属性，也就是服务名，创建一个空的基于注解的容器类，先判断configuration属性的Map里是否包含当前name，之前已经看到configuration的属性来源就是之前注入的FeignClientSpecification的name属性也就是服务名，所以传入的服务名是包含在这里的，判断获得当前name对应的FeignClientSpecification注册到新创建的容器类中，将NamedContextFactory的defaultConfigType属性注入到容器中类型为PropertyPlaceholderAutoConfiguration，当前defaultConfigType具体实现类是通过FeignContext的构造方法调用super也就是NamedContextFactory传参复制为FeignClientSpecification对象，propertySourceName属性添加到当前新创建的服务容器的MutablePropertySources中，并且规定读取的name是当前propertySourceName,的就是说每个服务名所创建的子容器是不同的，如果不特殊指定父容器，则他们的父容器是相同的，都是ApplicationContext，关于FeignClientSpecification在下一节详述

NamedContextFactory.java,getInstance() --> getContext() --> createContext()
public abstract class NamedContextFactory<C extends NamedContextFactory.Specification>
        implements DisposableBean, ApplicationContextAware {

    private Map<String, C> configurations = new ConcurrentHashMap<>();

    public <T> T getInstance(String name, Class<T> type) {
        AnnotationConfigApplicationContext context = getContext(name);
        if (BeanFactoryUtils.beanNamesForTypeIncludingAncestors(context,
                type).length > 0) {
            return context.getBean(type);
        }
        return null;
    }

    protected AnnotationConfigApplicationContext getContext(String name) {
        if (!this.contexts.containsKey(name)) {
            synchronized (this.contexts) {
                if (!this.contexts.containsKey(name)) {
                    this.contexts.put(name, createContext(name));
                }
            }
        }
        return this.contexts.get(name);
    }

    protected AnnotationConfigApplicationContext createContext(String name) {
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
        if (this.configurations.containsKey(name)) {
            for (Class<?> configuration : this.configurations.get(name)
                    .getConfiguration()) {
                context.register(configuration);
            }
        }
        for (Map.Entry<String, C> entry : this.configurations.entrySet()) {
            if (entry.getKey().startsWith("default.")) {
                for (Class<?> configuration : entry.getValue().getConfiguration()) {
                    context.register(configuration);
                }
            }
        }
        context.register(PropertyPlaceholderAutoConfiguration.class,
                this.defaultConfigType);
        context.getEnvironment().getPropertySources().addFirst(new MapPropertySource(
                this.propertySourceName,
                Collections.<String, Object> singletonMap(this.propertyName, name)));
        if (this.parent != null) {
            // Uses Environment from parent as well as beans
            context.setParent(this.parent);
        }
        context.refresh();
        return context;
    }
}

现在来看Feign.Builder builder = get(context, Feign.Builder.class)这一行代码，其实这一行代码是在FeignClientsConfiguration这个类完成创建并完成Bean对象的注入之后才会执行的，关于具体注入的对象在后面一个章节讲述，这里先大致说一下这一块代码的功能，创建Feign.Builder对象，并将容器中（FeignClientsConfiguration注入的几个Bean）对应的Bean调用setter方法来完成对Feign.Builder的logger-encoder, decoder, contract属性赋值

1.5 FeignClientsConfiguration

接着上面的代码，org.springframework.cloud.netflix.feign.FeignClientFactoryBean#feign里的FeignLoggerFactory loggerFactory = get(context, FeignLoggerFactory.class);代码，会去创建每个服务自己的容器，并且会去实例化当前配置类，下面就来看下该类的作用

@Configuration
public class FeignClientsConfiguration {
    @Autowired
    private ObjectFactory<HttpMessageConverters> messageConverters;
    @Autowired(required = false)
    private List<AnnotatedParameterProcessor> parameterProcessors = new ArrayList<>();
    @Autowired(required = false)
    private List<FeignFormatterRegistrar> feignFormatterRegistrars = new ArrayList<>();
    @Autowired(required = false)
    private Logger logger;
    @Bean
    @ConditionalOnMissingBean
    public Decoder feignDecoder() {
        return new ResponseEntityDecoder(new SpringDecoder(this.messageConverters));
    }
    @Bean
    @ConditionalOnMissingBean
    public Encoder feignEncoder() {
        return new SpringEncoder(this.messageConverters);
    }
    @Bean
    @ConditionalOnMissingBean
    public Contract feignContract(ConversionService feignConversionService) {
        return new SpringMvcContract(this.parameterProcessors, feignConversionService);
    }
    @Bean
    public FormattingConversionService feignConversionService() {
        FormattingConversionService conversionService = new DefaultFormattingConversionService();
        for (FeignFormatterRegistrar feignFormatterRegistrar : feignFormatterRegistrars) {
            feignFormatterRegistrar.registerFormatters(conversionService);
        }
        return conversionService;
    }
    @Configuration
    @ConditionalOnClass({ HystrixCommand.class, HystrixFeign.class })
    protected static class HystrixFeignConfiguration {
        @Bean
        @Scope("prototype")
        @ConditionalOnMissingBean
        @ConditionalOnProperty(name = "feign.hystrix.enabled", matchIfMissing = false)
        public Feign.Builder feignHystrixBuilder() {
            return HystrixFeign.builder();
        }
    }
    @Bean
    @ConditionalOnMissingBean
    public Retryer feignRetryer() {
        return Retryer.NEVER_RETRY;
    }
    @Bean
    @Scope("prototype")
    @ConditionalOnMissingBean
    public Feign.Builder feignBuilder(Retryer retryer) {
        return Feign.builder().retryer(retryer);
    }
    @Bean
    @ConditionalOnMissingBean(FeignLoggerFactory.class)
    public FeignLoggerFactory feignLoggerFactory() {
        return new DefaultFeignLoggerFactory(logger);
    }
}

① 该类为一个配置类，被实例化后，识别当前类下的注入的Bean，messageConverters，parameterProcessors,feignFormatterRegistrars,logger等允许注入，除messageConverters系统有默认值外，其它无默认值，但应该都可以自定义并注入容器，然后使之生效。同时下面默认也会像容器中注入几个Bean，前提是用户没有自定义的时候，如 feignDecoder()注入Decoder, feignEncoder注入Encoder， feignContract()注入Contract, feignConversionService注入FormattingConversionService,同样不细究作用；

② 有一个内部类，用来判断如果当前类路径下有Hystrix的包，则该配置类生效，并且如果配置了feign.hystrix.enabled属性，则使用Hystrix来构建HystrixFeign`

@Configuration
 @ConditionalOnClass({ HystrixCommand.class, HystrixFeign.class })
 protected static class HystrixFeignConfiguration {
  @Bean
  @Scope("prototype")
  @ConditionalOnMissingBean
  @ConditionalOnProperty(name = "feign.hystrix.enabled", matchIfMissing = false)
  public Feign.Builder feignHystrixBuilder() {
   return HystrixFeign.builder();
  }
 }

③ feignRetryer，可以看到Feign的重试机制默认是关闭的，该接口有一个内部类，目前调用的是空参的构造函数

@Bean
 @ConditionalOnMissingBean
 public Retryer feignRetryer() {
  return Retryer.NEVER_RETRY;
 }

④ feignBuilder()方法，构建一个默认的的Feign.Builder对象,入参的retryer会从容器中获取注入的Retryer来覆盖默认的builder中的Retryer没有任何属性，目前容器中已经通过③的方法feignRetryer()来注入了一个Retryer.NEVER_RETRY类型的Retryer,所以会覆盖默认的Feign.builder()构建出来的重试机制，即不提供重试支持，默认值详见⑤

 @Bean
 @Scope("prototype")
 @ConditionalOnMissingBean
 public Feign.Builder feignBuilder(Retryer retryer) {
  return Feign.builder().retryer(retryer);
 }

这里执行结束后，各个参数的 值如下图

⑤ Feign.Builder对象,看一下内部类Builder，这一块的步骤往下细分一下，其实会覆盖某些之前设置的属性，下面来详细看一下每个方法的默认实现,某些方法不再贴里面的具体实现，到时候可以自行进入某些方法内部查看源码

public abstract class Feign {
  public static Builder builder() {
    return new Builder();
  }
public static class Builder {
    private final List<RequestInterceptor> requestInterceptors =
        new ArrayList<RequestInterceptor>();
    // 默认的日志级别，可选值有NONE, BASIC, HEADERS, FULL
    private Logger.Level logLevel = Logger.Level.NONE;
   // Defines what annotations and values are valid on interfaces.
    private Contract contract = new Contract.Default();
    // 提交一个feign.Request的http请求，该实现是线程安全的
    private Client client = new Client.Default(null, null);
   // 默认的重试机制，有几个属性period为100，maxPeriod为1000，maxAttempts为5，attempt为1，sleptForMillis为0
    private Retryer retryer = new Retryer.Default();
    // 没有任何属性的logger
    private Logger logger = new NoOpLogger();
   // 编码
    private Encoder encoder = new Encoder.Default();
    // 解码
    private Decoder decoder = new Decoder.Default();
    // 允许自定义对响应异常的处理
    private ErrorDecoder errorDecoder = new ErrorDecoder.Default();
   // 默认的Request.Options，connectTimeoutMillis为10 * 1000， readTimeoutMillis为60 * 1000
    private Options options = new Options();
   // Controls reflective method dispatch.
    private InvocationHandlerFactory invocationHandlerFactory =
        new InvocationHandlerFactory.Default();
    private boolean decode404;
｝

1.6 FeignClientProperties

① 配置前缀feign.client

@ConfigurationProperties("feign.client")
public class FeignClientProperties {
     private boolean defaultToProperties = true;
     private String defaultConfig = "default";
     private Map<String, FeignClientConfiguration> config = new HashMap<>();
}

② 该类有一个内部类FeignClientConfiguration，通过config属性的setter/getter方法来将该内部类赋值给该类的属性，而且该属性是一个map形式，value才是内部类，所以再配置属性的时候，可以指定一个Key,所以如果需要配置FeignClientConfiguration下的属性，经后面分析，为什么使用map形式存储属性对象，是因为当前项目需要调用多个项目的Feign接口，所以可以使用注册的服务名为每个服务单独设置不同的属性，而如果需要所有的服务公用的配置，则配置在default这个key下，为什么是default，是因为取值属性defaultConfig,需要使用feign.client.key.config，可配置属性如下

feign:
  client:
    myFeign:
        readTimeout: 5000
        connectTimeout: 2000
    default:
        readTimeout: 6000
        connectTimeout: 3000

public static class FeignClientConfiguration {
  private Logger.Level loggerLevel;
  private Integer connectTimeout;
  private Integer readTimeout;
  private Class<Retryer> retryer;
  private Class<ErrorDecoder> errorDecoder;
  private List<Class<RequestInterceptor>> requestInterceptors;
  private Boolean decode404;
}

1.7 再看FeignClientFactoryBean

接之前已经露过面的一次configureFeign()方法，这个方法获取了上面FeignClientProperties这个bean，在这里会初始化FeignClientProperties的各种属性，FeignClientProperties有一个属性defaultToProperties默认为true,所以走的是if里的方法，代码如下，

class FeignClientFactoryBean implements FactoryBean<Object>, InitializingBean,
        ApplicationContextAware {

        @Override
    public Object getObject() throws Exception {
        FeignContext context = applicationContext.getBean(FeignContext.class);
        Feign.Builder builder = feign(context);
        if (!StringUtils.hasText(this.url)) {
            String url;
            if (!this.name.startsWith("http")) {
                url = "http://" + this.name;
            }
            else {
                url = this.name;
            }
            url += cleanPath();
            return loadBalance(builder, context, new HardCodedTarget<>(this.type,
                    this.name, url));
        }
        if (StringUtils.hasText(this.url) && !this.url.startsWith("http")) {
            this.url = "http://" + this.url;
        }
        String url = this.url + cleanPath();
        Client client = getOptional(context, Client.class);
        if (client != null) {
            if (client instanceof LoadBalancerFeignClient) {
                // not lod balancing because we have a url,
                // but ribbon is on the classpath, so unwrap
                client = ((LoadBalancerFeignClient)client).getDelegate();
            }
            builder.client(client);
        }
        Targeter targeter = get(context, Targeter.class);
        return targeter.target(this, builder, context, new HardCodedTarget<>(
                this.type, this.name, url));
    }

    protected Feign.Builder feign(FeignContext context) {
        FeignLoggerFactory loggerFactory = get(context, FeignLoggerFactory.class);
        Logger logger = loggerFactory.create(this.type);
        // @formatter:off
        Feign.Builder builder = get(context, Feign.Builder.class)
                // required values
                .logger(logger)
                .encoder(get(context, Encoder.class))
                .decoder(get(context, Decoder.class))
                .contract(get(context, Contract.class));
        // @formatter:on
        configureFeign(context, builder);
        return builder;
    }
    protected void configureFeign(FeignContext context, Feign.Builder builder) {
        FeignClientProperties properties = applicationContext.getBean(FeignClientProperties.class);
        if (properties != null) {
            if (properties.isDefaultToProperties()) {
                configureUsingConfiguration(context, builder);
                configureUsingProperties(properties.getConfig().get(properties.getDefaultConfig()), builder);
                configureUsingProperties(properties.getConfig().get(this.name), builder);
            } else {
                configureUsingProperties(properties.getConfig().get(properties.getDefaultConfig()), builder);
                configureUsingProperties(properties.getConfig().get(this.name), builder);
                configureUsingConfiguration(context, builder);
            }
        } else {
            configureUsingConfiguration(context, builder);
        }
    }

    protected void configureUsingConfiguration(FeignContext context, Feign.Builder builder) {
        Logger.Level level = getOptional(context, Logger.Level.class);
        if (level != null) {
            builder.logLevel(level);
        }
        Retryer retryer = getOptional(context, Retryer.class);
        if (retryer != null) {
            builder.retryer(retryer);
        }
        ErrorDecoder errorDecoder = getOptional(context, ErrorDecoder.class);
        if (errorDecoder != null) {
            builder.errorDecoder(errorDecoder);
        }
        Request.Options options = getOptional(context, Request.Options.class);
        if (options != null) {
            builder.options(options);
        }
        Map<String, RequestInterceptor> requestInterceptors = context.getInstances(
                this.name, RequestInterceptor.class);
        if (requestInterceptors != null) {
            builder.requestInterceptors(requestInterceptors.values());
        }
        if (decode404) {
            builder.decode404();
        }
    }
    protected void configureUsingProperties(FeignClientProperties.FeignClientConfiguration config, Feign.Builder builder) {
        if (config == null) {
            return;
        }
        if (config.getLoggerLevel() != null) {
            builder.logLevel(config.getLoggerLevel());
        }
        if (config.getConnectTimeout() != null && config.getReadTimeout() != null) {
            builder.options(new Request.Options(config.getConnectTimeout(), config.getReadTimeout()));
        }
        if (config.getRetryer() != null) {
            Retryer retryer = getOrInstantiate(config.getRetryer());
            builder.retryer(retryer);
        }
        if (config.getErrorDecoder() != null) {
            ErrorDecoder errorDecoder = getOrInstantiate(config.getErrorDecoder());
            builder.errorDecoder(errorDecoder);
        }
        if (config.getRequestInterceptors() != null && !config.getRequestInterceptors().isEmpty()) {
            // this will add request interceptor to builder, not replace existing
            for (Class<RequestInterceptor> bean : config.getRequestInterceptors()) {
                RequestInterceptor interceptor = getOrInstantiate(bean);
                builder.requestInterceptor(interceptor);
            }
        }
        if (config.getDecode404() != null) {
            if (config.getDecode404()) {
                builder.decode404();
            }
        }
    }
}

① 先看方法configureUsingConfiguration,从FeignContext中获取这些bean如果不为空的话，就覆盖之前做的默认值，所以如果我们自定义这些bean的放入到容器的时候，则从FeignContext中一旦能够获取到这些bean，就可以覆盖到系统默认的处理，这里给我们自定义留下了支持

configureUsingConfiguration(context, builder);
protected void configureUsingConfiguration(FeignContext context, Feign.Builder builder) {
    // 目前容器没有注入`Logger.Level`，所以这里使用的还是Feign.Builder的默认值
    Logger.Level level = getOptional(context, Logger.Level.class);
    if (level != null) {
        builder.logLevel(level);
    }
    // 参考FeignClientsConfiguration，容器中默认注入了一个`Retryer.NEVER_RETRY`
    Retryer retryer = getOptional(context, Retryer.class);
    if (retryer != null) {
        builder.retryer(retryer);
    }
    // 没有注入`ErrorDecoder`，所以使用的还是Feign.Builder的默认值
    ErrorDecoder errorDecoder = getOptional(context, ErrorDecoder.class);
    if (errorDecoder != null) {
        builder.errorDecoder(errorDecoder);
    }
    // 默认通过`FeignRibbonClientAutoConfiguration`的`feignRequestOptions()`方        // 注入了一个Request.Options
    // 详见下一节FeignRibbonClientAutoConfiguration，拿到这个`bean`，覆盖原属性
    Request.Options options = getOptional(context, Request.Options.class);
    if (options != null) {
        builder.options(options);
    }
    // 未细究
    Map<String, RequestInterceptor> requestInterceptors = context.getInstances(
        this.name, RequestInterceptor.class);
    if (requestInterceptors != null) {
        builder.requestInterceptors(requestInterceptors.values());
    }
    // 未细究
    if (decode404) {
        builder.decode404();
    }
}

② configureUsingProperties(properties.getConfig().get(properties.getDefaultConfig()), builder)方法，作用是应用配置文件中的默认的配置,properties的类型为FeignClientProperties，config形式为Map，相关细节在FeignClientProperties这一节已详细讲解，所以这里是把配置文件下的feign.client.default下的属性应用起来，可以配置的属性有如下方法内部，可以看到按照顺序，默认配置会覆盖第一步里的配置，配置文件的优先级高于配置类的优先级（包括使用配置类的方法注入自定义的bean）

configureUsingProperties(properties.getConfig().get(properties.getDefaultConfig()), builder)
protected void configureUsingProperties(FeignClientProperties.FeignClientConfiguration config, Feign.Builder builder) {
    if (config == null) {
        return;
    }
    if (config.getLoggerLevel() != null) {
        builder.logLevel(config.getLoggerLevel());
    }
    if (config.getConnectTimeout() != null && config.getReadTimeout() != null) {
        builder.options(new Request.Options(config.getConnectTimeout(), config.getReadTimeout()));
    }
    if (config.getRetryer() != null) {
        Retryer retryer = getOrInstantiate(config.getRetryer());
        builder.retryer(retryer);
    }
    if (config.getErrorDecoder() != null) {
        ErrorDecoder errorDecoder = getOrInstantiate(config.getErrorDecoder());
        builder.errorDecoder(errorDecoder);
    }
    if (config.getRequestInterceptors() != null && !config.getRequestInterceptors().isEmpty()) {
        // this will add request interceptor to builder, not replace existing
        for (Class<RequestInterceptor> bean : config.getRequestInterceptors()) {
            RequestInterceptor interceptor = getOrInstantiate(bean);
            builder.requestInterceptor(interceptor);
        }
    }
    if (config.getDecode404() != null) {
        if (config.getDecode404()) {
            builder.decode404();
        }
    }
}

③ configureUsingProperties(properties.getConfig().get(this.name), builder);作用是应用当前Feign应用特有的属性配置，可配置的属性与上面一样，但是属性类放入config属性Map的key为Feign接口应用的名称

④ properties.isDefaultToProperties()，defaultToProperties的默认值为true,如果为true,则应用配置的顺序是先应用属性类的key和自己应用一样名称的配置，然后再应用default的配置，最后应用配置类的属性；而如果这个属性的值为false,则应用顺序正好相反

⑤ feign()方法执行完成之后，回到getObject()方法，该类的type属性是每个标注了@FeignClient接口类，判断注解中是否明确了url地址，如果没有的话，下面判断来定义url的规则为http://name/path即服务名和注解指定的path属性，即应用的ContextPath和每个接口类的具体实现类的@RequestMapping，new HardCodedTarget<>(this.type, this.name, url)生成调用目标地址信息的代理类

1.8 FeignRibbonClientAutoConfiguration

该类位于Feign包下的ribbon包下，Feign的负载均衡是基于ribbon的，该类的全路径为org.springframework.cloud.netflix.feign.ribbon.FeignRibbonClientAutoConfiguration，

该类代码如下：

@ConditionalOnClass({ ILoadBalancer.class, Feign.class })
@Configuration
@AutoConfigureBefore(FeignAutoConfiguration.class)
@EnableConfigurationProperties({ FeignHttpClientProperties.class })
//Order is important here, last should be the default, first should be optional
// see https://github.com/spring-cloud/spring-cloud-netflix/issues/2086#issuecomment-316281653
@Import({ HttpClientFeignLoadBalancedConfiguration.class,
  OkHttpFeignLoadBalancedConfiguration.class,
  DefaultFeignLoadBalancedConfiguration.class })
public class FeignRibbonClientAutoConfiguration {
 @Bean
 @Primary
 @ConditionalOnMissingClass("org.springframework.retry.support.RetryTemplate")
 public CachingSpringLoadBalancerFactory cachingLBClientFactory(
   SpringClientFactory factory) {
  return new CachingSpringLoadBalancerFactory(factory);
 }
 @Bean
 @Primary
 @ConditionalOnClass(name = "org.springframework.retry.support.RetryTemplate")
 public CachingSpringLoadBalancerFactory retryabeCachingLBClientFactory(
  SpringClientFactory factory,
  LoadBalancedRetryPolicyFactory retryPolicyFactory,
  LoadBalancedBackOffPolicyFactory loadBalancedBackOffPolicyFactory,
  LoadBalancedRetryListenerFactory loadBalancedRetryListenerFactory) {
  return new CachingSpringLoadBalancerFactory(factory, retryPolicyFactory, loadBalancedBackOffPolicyFactory, loadBalancedRetryListenerFactory);
 }
 @Bean
 @ConditionalOnMissingBean
 public Request.Options feignRequestOptions() {
  return LoadBalancerFeignClient.DEFAULT_OPTIONS;
 }
}

① 先看方法feignRequestOptions()， @ConditionalOnMissingBean注解，如果当前项目中还没有Request.Options这个Bean则注入这个Bean，属于默认配置，可以看到如果自定义这个Bean的注入，则这里的代码会失效。然后参考上一节的FeignClientFactoryBean的configureUsingConfiguration()方法，则我们注入的bean会生效。来看一下系统的默认配置，可以看到最终请求Request.Options.的 connectTimeoutMillis的默认值为10 * 1000， readTimeoutMillis的默认值为60 * 1000

 @Bean
 @ConditionalOnMissingBean
 public Request.Options feignRequestOptions() {
  return LoadBalancerFeignClient.DEFAULT_OPTIONS;
 }
// 如上方法指向了这里
public class LoadBalancerFeignClient implements Client {
 static final Request.Options DEFAULT_OPTIONS = new Request.Options();
}
// 如上方法指向了这里
public final class Request {
public static class Options {
    private final int connectTimeoutMillis;
    private final int readTimeoutMillis;
    public Options(int connectTimeoutMillis, int readTimeoutMillis) {
      this.connectTimeoutMillis = connectTimeoutMillis;
      this.readTimeoutMillis = readTimeoutMillis;
    }
    public Options() {
      this(10 * 1000, 60 * 1000);
    }
}

1.9 LoadBalancerFeignClient

客户端调用Feign接口通过反射最终执行如下方法

@Override
 public Response execute(Request request, Request.Options options) throws IOException {
  try {
   URI asUri = URI.create(request.url());
   String clientName = asUri.getHost();
   URI uriWithoutHost = cleanUrl(request.url(), clientName);
   FeignLoadBalancer.RibbonRequest ribbonRequest = new FeignLoadBalancer.RibbonRequest(
     this.delegate, request, uriWithoutHost);
   IClientConfig requestConfig = getClientConfig(options, clientName);
   return lbClient(clientName).executeWithLoadBalancer(ribbonRequest,
     requestConfig).toResponse();
  }
  catch (ClientException e) {
   IOException io = findIOException(e);
   if (io != null) {
    throw io;
   }
   throw new RuntimeException(e);
  }
 }

request包含当前请求信息url,head,body，charset，如下图

options包含连接connectTimeoutMillis和readTimeoutMillis，这个在前面已经看到默认分别是10000和60000,关于如何zi自定义配置前面也已经说过

方法体内代码asUri为完整请求地址，包含请求协议://服务名/服务上下文/请求映射路径+参数,clientName为解析请求中的服务名,uriWithoutHost解析请求地址去除服务名,下一步构建FeignLoadBalancer.RibbonRequest对象ribbonRequest，其中this.delegate的类型为feign.Client，默认使用的是它的实现类Client.Default，构建步骤具体为下，直接贴代码看一眼就行,其中Uri往下看似乎已经是经过UTF-8编码过了，但是body没有经过编码,总体而言该对象包含了当前请求所需要的重要信息 this.delegate的赋值通过以下类指定

@Configuration
class DefaultFeignLoadBalancedConfiguration {
 @Bean
 @ConditionalOnMissingBean
 public Client feignClient(CachingSpringLoadBalancerFactory cachingFactory,
         SpringClientFactory clientFactory) {
  return new LoadBalancerFeignClient(new Client.Default(null, null),
    cachingFactory, clientFactory);
 }
}

构建Request请求信息

RibbonRequest(Client client, Request request, URI uri) {
   this.client = client;
   setUri(uri);
   this.request = toRequest(request);
  }
private Request toRequest(Request request) {
   Map<String, Collection<String>> headers = new LinkedHashMap<>(
     request.headers());
   return Request.create(request.method(),getUri().toASCIIString(),headers,request.body(),request.charset());
  }

下面来看下面的代码调用了一个方法getClientConfig(),可以看到这里配置IClientConfig对象的时候如果options使用的是系统默认的对象时，则会触发方法getClientConfig(),而如果不是由系统默认的这个对象，而是我们自己自定义注入过这个对象（无论是配置类还是配置文件），则会触发代码new FeignOptionsClientConfig(options);

IClientConfig requestConfig = getClientConfig(options, clientName);
// 方法内部
IClientConfig getClientConfig(Request.Options options, String clientName) {
  IClientConfig requestConfig;
  if (options == DEFAULT_OPTIONS) {
   requestConfig = this.clientFactory.getClientConfig(clientName);
  } else {
   requestConfig = new FeignOptionsClientConfig(options);
  }
  return requestConfig;
 }

先看简单的requestConfig = new FeignOptionsClientConfig(options);该方法内部如下，则可以看到最终IClientConfig 对象只会有两个属性，一个CommonClientConfigKey.ConnectTimeout，一个CommonClientConfigKey.ReadTimeout，而且两个值的属性使我们自定义的；

public FeignOptionsClientConfig(Request.Options options) {
   setProperty(CommonClientConfigKey.ConnectTimeout,
     options.connectTimeoutMillis());
   setProperty(CommonClientConfigKey.ReadTimeout, options.readTimeoutMillis());
  }

现在来看如果没有修改过默认的请求属性options == DEFAULT_OPTIONS，这一块看的有点晕乎，在之前看到Feign如果没有任何配置，系统已经默认了connectTimeoutMillis和readTimeoutMillis，这个在前面已经看到默认分别是10000和60000，但是代码在这里处理判断如果使用的是默认的,加载的属性列表如下，会对之前所有的默认操作进行覆盖

2.0 FeignLoadBalancer

@Override
 public RibbonResponse execute(RibbonRequest request, IClientConfig configOverride)
   throws IOException {
  Request.Options options;
  if (configOverride != null) {
   options = new Request.Options(
     configOverride.get(CommonClientConfigKey.ConnectTimeout,
       this.connectTimeout),
     (configOverride.get(CommonClientConfigKey.ReadTimeout,
       this.readTimeout)));
  }
  else {
   options = new Request.Options(this.connectTimeout, this.readTimeout);
  }
  Response response = request.client().execute(request.toRequest(), options);
  return new RibbonResponse(request.getUri(), response);
 }

如果在之前没有对Feign进行过任何配置，那么这里就会加载默认的属性，一旦加载默认的属性，则目前调试下来会有40个属性，默认的ReadTimeout=1000, ConnectTimeout=1000,如下图所示

如果我们自定义过当前请求Feign的属性，那么IClientConfig对象则会有我们设置的属性以及值，比如我们设置了如下配置则，当前configOverride就会有这两个属性的值，而不是默认的40个。目前还没搞清楚其余字段的意思

feign:
 client:
  config:
   default:
     readTimeout: 3333
     connectTimeout: 4444

依然是上面的execute()方法，代码从入参之后继续往下走，现在看到new 了一个新的Request.Options对象，下面判断configOverride是否为空，经过上面的描述，这个对象不为空，如果我们自定义过，则会有两个属性，如果没有自定义过，则会有默认的属性，通过configOverride来构建Request.Options对象的代码，可以看到其实仅仅用到了ConnectTimeout和ReadTimeout两个属性，然后调用Request.Options的构造方法来进行赋值，构造方法如下：

    public Options(int connectTimeoutMillis, int readTimeoutMillis) {
      this.connectTimeoutMillis = connectTimeoutMillis;
      this.readTimeoutMillis = readTimeoutMillis;
    }

自此Request.Options对象的两个属性connectTimeoutMillis和readTimeoutMillis的属性处理完成

以上为个人经验，希望能给大家一个参考，也希望大家多多支持我们。