使用HttpClient和OkHttp
在Feign中，Client是一个非常重要的组件，Feign最终发送Request请求以及接收Response响应都是由Client组件来完成的。Client在Feign源码中是一个接口，在默认情况下，Client的实现类是Client.Default。Client.Default是由HttpURLConnection来实现网络请求的。另外,Client还支持HttpClient和OkHttp来进行网络请求。
首先查看FeignRibbonClient的自动配置类FeignRibbonClientAutoConfiguration，该类在程序启动的时候注入一些Bean，其中注入了一个BeanName为feignClient的Client类型的Bean。在省缺配置BeanName为FeignClient的Bean的情况下，会自动注入Client.Default这个对象，跟踪Client.Default源码,Client.Default使用的网络请求框架是HttpURLConnection，代码如下：
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public static class Default implements Client { private final SSLSocketFactory sslContextFactory; private final HostnameVerifier hostnameVerifier;
public Default(SSLSocketFactory sslContextFactory, HostnameVerifier hostnameVerifier) { this .sslContextFactory = sslContextFactory; this .hostnameVerifier = hostnameVerifier; }
public Response execute(Request request, Options options) throws IOException { HttpURLConnection connection = this .convertAndSend(request, options); return this .convertResponse(connection, request); } ...... //代码省略 } |
这种情况下，由于缺乏连接池的支持，在达到一定流量的后服务肯定会出问题 。
使用HttpClient
那么如何在Feign中使用HttpClient的框架呢？我们查看FeignAutoConfiguration.HttpClientFeignConfiguration的源码：
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@Configuration @ConditionalOnClass ({ApacheHttpClient. class }) @ConditionalOnMissingClass ({ "com.netflix.loadbalancer.ILoadBalancer" }) @ConditionalOnMissingBean ({CloseableHttpClient. class }) @ConditionalOnProperty ( value = { "feign.httpclient.enabled" }, matchIfMissing = true ) protected static class HttpClientFeignConfiguration { private final Timer connectionManagerTimer = new Timer( "FeignApacheHttpClientConfiguration.connectionManagerTimer" , true ); @Autowired ( required = false ) private RegistryBuilder registryBuilder; private CloseableHttpClient httpClient;
protected HttpClientFeignConfiguration() { }
@Bean @ConditionalOnMissingBean ({HttpClientConnectionManager. class }) public HttpClientConnectionManager connectionManager(ApacheHttpClientConnectionManagerFactory connectionManagerFactory, FeignHttpClientProperties httpClientProperties) { final HttpClientConnectionManager connectionManager = connectionManagerFactory.newConnectionManager(httpClientProperties.isDisableSslValidation(), httpClientProperties.getMaxConnections(), httpClientProperties.getMaxConnectionsPerRoute(), httpClientProperties.getTimeToLive(), httpClientProperties.getTimeToLiveUnit(), this .registryBuilder); this .connectionManagerTimer.schedule( new TimerTask() { public void run() { connectionManager.closeExpiredConnections(); } }, 30000L, ( long )httpClientProperties.getConnectionTimerRepeat()); return connectionManager; }
@Bean public CloseableHttpClient httpClient(ApacheHttpClientFactory httpClientFactory, HttpClientConnectionManager httpClientConnectionManager, FeignHttpClientProperties httpClientProperties) { RequestConfig defaultRequestConfig = RequestConfig.custom().setConnectTimeout(httpClientProperties.getConnectionTimeout()).setRedirectsEnabled(httpClientProperties.isFollowRedirects()).build(); this .httpClient = httpClientFactory.createBuilder().setConnectionManager(httpClientConnectionManager).setDefaultRequestConfig(defaultRequestConfig).build(); return this .httpClient; }
@Bean @ConditionalOnMissingBean ({Client. class }) public Client feignClient(HttpClient httpClient) { return new ApacheHttpClient(httpClient); }
@PreDestroy public void destroy() throws Exception { this .connectionManagerTimer.cancel(); if ( this .httpClient != null ) { this .httpClient.close(); }
} } |
从代码@ConditionalOnClass({ApacheHttpClient.class})注解可知，只需要在pom文件上加上HttpClient依赖即可。另外需要在配置文件中配置feign.httpclient.enabled为true，从@ConditionalOnProperty注解可知，这个配置可以不写，因为在默认情况下就为true:
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< dependency > < groupId >io.github.openfeign</ groupId > < artifactId >feign-httpclient</ artifactId > < version >9.4.0</ version > </ dependency > |
使用OkHttp
查看FeignAutoConfiguration.HttpClientFeignConfiguration的源码：
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@Configuration @ConditionalOnClass ({OkHttpClient. class }) @ConditionalOnMissingClass ({ "com.netflix.loadbalancer.ILoadBalancer" }) @ConditionalOnMissingBean ({okhttp3.OkHttpClient. class }) @ConditionalOnProperty ({ "feign.okhttp.enabled" }) protected static class OkHttpFeignConfiguration { private okhttp3.OkHttpClient okHttpClient;
protected OkHttpFeignConfiguration() { }
@Bean @ConditionalOnMissingBean ({ConnectionPool. class }) public ConnectionPool httpClientConnectionPool(FeignHttpClientProperties httpClientProperties, OkHttpClientConnectionPoolFactory connectionPoolFactory) { Integer maxTotalConnections = httpClientProperties.getMaxConnections(); Long timeToLive = httpClientProperties.getTimeToLive(); TimeUnit ttlUnit = httpClientProperties.getTimeToLiveUnit(); return connectionPoolFactory.create(maxTotalConnections, timeToLive, ttlUnit); }
@Bean public okhttp3.OkHttpClient client(OkHttpClientFactory httpClientFactory, ConnectionPool connectionPool, FeignHttpClientProperties httpClientProperties) { Boolean followRedirects = httpClientProperties.isFollowRedirects(); Integer connectTimeout = httpClientProperties.getConnectionTimeout(); Boolean disableSslValidation = httpClientProperties.isDisableSslValidation(); this .okHttpClient = httpClientFactory.createBuilder(disableSslValidation).connectTimeout(( long )connectTimeout, TimeUnit.MILLISECONDS).followRedirects(followRedirects).connectionPool(connectionPool).build(); return this .okHttpClient; }
@PreDestroy public void destroy() { if ( this .okHttpClient != null ) { this .okHttpClient.dispatcher().executorService().shutdown(); this .okHttpClient.connectionPool().evictAll(); }
}
@Bean @ConditionalOnMissingBean ({Client. class }) public Client feignClient(okhttp3.OkHttpClient client) { return new OkHttpClient(client); } } |
同理，如果想要在Feign中使用OkHttp作为网络请求框架，则只需要在pom文件中加上feign-okhttp的依赖，代码如下：
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< dependency > < groupId >io.github.openfeign</ groupId > < artifactId >feign-okhttp</ artifactId > < version >10.2.0</ version > </ dependency > |
OpenFeign替换为OkHttp
pom中引入feign-okhttp
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< dependency > < groupId >io.github.openfeign</ groupId > < artifactId >feign-okhttp</ artifactId > </ dependency > |
在application.yml中配置okhttp
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feign: httpclient: connection-timeout: 2000 #单位ms,默认2000 max-connections: 200 #线程池最大连接数 okhttp: enabled: true |
经过上面设置已经可以使用okhttp了，因为在FeignAutoConfiguration中已实现自动装配
如果需要对okhttp做更精细的参数设置，那需要自定义okhttp的实现，可以模仿上图中的实现
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。
原文链接：https://blog.csdn.net/u010277958/article/details/88730889
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