序
本文主要研究一下spring cloud的FeignClientFactoryBean
FeignClientFactoryBean
spring-cloud-openfeign-core-2.2.0.M1-sources.jar!/org/springframework/cloud/openfeign/FeignClientFactoryBean.java
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 contextId; 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.contextId, "Context id must be set"); Assert.hasText(this.name, "Name must be set"); } @Override public Object getObject() throws Exception { return getTarget(); } @Override public Class<?> getObjectType() { return this.type; } @Override public boolean isSingleton() { return true; } @Override public void setApplicationContext(ApplicationContext context) throws BeansException { this.applicationContext = context; } <T> T getTarget() { FeignContext context = this.applicationContext.getBean(FeignContext.class); Feign.Builder builder = feign(context); if (!StringUtils.hasText(this.url)) { if (!this.name.startsWith("http")) { this.url = "http://" + this.name; } else { this.url = this.name; } this.url += cleanPath(); return (T) loadBalance(builder, context, new HardCodedTarget<>(this.type, this.name, this.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 load 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 (T) targeter.target(this, builder, context, new HardCodedTarget<>(this.type, this.name, url)); } private String cleanPath() { String path = this.path.trim(); if (StringUtils.hasLength(path)) { if (!path.startsWith("/")) { path = "/" + path; } if (path.endsWith("/")) { path = path.substring(0, path.length() - 1); } } return path; } //......}- FeignClientFactoryBean实现了FactoryBean的getObject、getObjectType、isSingleton方法；实现了InitializingBean的afterPropertiesSet方法；实现了ApplicationContextAware的setApplicationContext方法
- getObject调用的是getTarget方法，它从applicationContext取出FeignContext，然后构造Feign.Builder并设置了logger、encoder、decoder、contract，之后通过configureFeign根据FeignClientProperties来进一步配置Feign.Builder的retryer、errorDecoder、request.Options、requestInterceptors、queryMapEncoder、decode404
- 初步配置完Feign.Builder之后再判断是否需要loadBalance，如果需要则通过loadBalance方法来设置，不需要则在Client是LoadBalancerFeignClient的时候进行unwrap
FeignClientProperties
spring-cloud-openfeign-core-2.2.0.M1-sources.jar!/org/springframework/cloud/openfeign/FeignClientProperties.java
@ConfigurationProperties("feign.client")public class FeignClientProperties { private boolean defaultToProperties = true; private String defaultConfig = "default"; private Map<String, FeignClientConfiguration> config = new HashMap<>(); public boolean isDefaultToProperties() { return this.defaultToProperties; } public void setDefaultToProperties(boolean defaultToProperties) { this.defaultToProperties = defaultToProperties; } public String getDefaultConfig() { return this.defaultConfig; } public void setDefaultConfig(String defaultConfig) { this.defaultConfig = defaultConfig; } public Map<String, FeignClientConfiguration> getConfig() { return this.config; } public void setConfig(Map<String, FeignClientConfiguration> config) { this.config = config; } @Override public boolean equals(Object o) { if (this == o) { return true; } if (o == null || getClass() != o.getClass()) { return false; } FeignClientProperties that = (FeignClientProperties) o; return this.defaultToProperties == that.defaultToProperties && Objects.equals(this.defaultConfig, that.defaultConfig) && Objects.equals(this.config, that.config); } @Override public int hashCode() { return Objects.hash(this.defaultToProperties, this.defaultConfig, this.config); } /** * Feign client configuration. */ 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; private Class<Decoder> decoder; private Class<Encoder> encoder; private Class<Contract> contract; public Logger.Level getLoggerLevel() { return this.loggerLevel; } public void setLoggerLevel(Logger.Level loggerLevel) { this.loggerLevel = loggerLevel; } public Integer getConnectTimeout() { return this.connectTimeout; } public void setConnectTimeout(Integer connectTimeout) { this.connectTimeout = connectTimeout; } public Integer getReadTimeout() { return this.readTimeout; } public void setReadTimeout(Integer readTimeout) { this.readTimeout = readTimeout; } public Class<Retryer> getRetryer() { return this.retryer; } public void setRetryer(Class<Retryer> retryer) { this.retryer = retryer; } public Class<ErrorDecoder> getErrorDecoder() { return this.errorDecoder; } public void setErrorDecoder(Class<ErrorDecoder> errorDecoder) { this.errorDecoder = errorDecoder; } public List<Class<RequestInterceptor>> getRequestInterceptors() { return this.requestInterceptors; } public void setRequestInterceptors( List<Class<RequestInterceptor>> requestInterceptors) { this.requestInterceptors = requestInterceptors; } public Boolean getDecode404() { return this.decode404; } public void setDecode404(Boolean decode404) { this.decode404 = decode404; } public Class<Decoder> getDecoder() { return this.decoder; } public void setDecoder(Class<Decoder> decoder) { this.decoder = decoder; } public Class<Encoder> getEncoder() { return this.encoder; } public void setEncoder(Class<Encoder> encoder) { this.encoder = encoder; } public Class<Contract> getContract() { return this.contract; } public void setContract(Class<Contract> contract) { this.contract = contract; } @Override public boolean equals(Object o) { if (this == o) { return true; } if (o == null || getClass() != o.getClass()) { return false; } FeignClientConfiguration that = (FeignClientConfiguration) o; return this.loggerLevel == that.loggerLevel && Objects.equals(this.connectTimeout, that.connectTimeout) && Objects.equals(this.readTimeout, that.readTimeout) && Objects.equals(this.retryer, that.retryer) && Objects.equals(this.errorDecoder, that.errorDecoder) && Objects.equals(this.requestInterceptors, that.requestInterceptors) && Objects.equals(this.decode404, that.decode404) && Objects.equals(this.encoder, that.encoder) && Objects.equals(this.decoder, that.decoder) && Objects.equals(this.contract, that.contract); } @Override public int hashCode() { return Objects.hash(this.loggerLevel, this.connectTimeout, this.readTimeout, this.retryer, this.errorDecoder, this.requestInterceptors, this.decode404, this.encoder, this.decoder, this.contract); } }}- FeignClientProperties有个Map结构的config，key是feign client的名称，默认是default，value是FeignClientConfiguration；FeignClientConfiguration包含了loggerLevel、connectTimeout、readTimeout、retryer、errorDecoder、requestInterceptors、decode404、decoder、encoder、contract属性
小结
- FeignClientFactoryBean实现了FactoryBean的getObject、getObjectType、isSingleton方法；实现了InitializingBean的afterPropertiesSet方法；实现了ApplicationContextAware的setApplicationContext方法
- getObject调用的是getTarget方法，它从applicationContext取出FeignContext，然后构造Feign.Builder并设置了logger、encoder、decoder、contract，之后通过configureFeign根据FeignClientProperties来进一步配置Feign.Builder的retryer、errorDecoder、request.Options、requestInterceptors、queryMapEncoder、decode404
- 初步配置完Feign.Builder之后再判断是否需要loadBalance，如果需要则通过loadBalance方法来设置，不需要则在Client是LoadBalancerFeignClient的时候进行unwrap
doc
- FeignClientFactoryBean