使用HttpClient和OkHttp
在Feign中，Client是一個非常重要的組件，Feign最終發送Request請求以及接收Response響應都是由Client組件來完成的。Client在Feign源碼中是一個接口，在默認情況下，Client的實現類是Client.Default。Client.Default是由HttpURLConnection來實現網絡請求的。另外,Client還支持HttpClient和OkHttp來進行網絡請求。
首先查看FeignRibbonClient的自動配置類FeignRibbonClientAutoConfiguration，該類在程序啟動的時候注入一些Bean，其中注入了一個BeanName為feignClient的Client類型的Bean。在省缺配置BeanName為FeignClient的Bean的情況下，會自動注入Client.Default這個對象，跟蹤Client.Default源碼,Client.Default使用的網絡請求框架是HttpURLConnection，代碼如下：
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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); } ......//代碼省略} |
這種情況下，由于缺乏連接池的支持，在達到一定流量的后服務肯定會出問題 。
使用HttpClient
那么如何在Feign中使用HttpClient的框架呢？我們查看FeignAutoConfiguration.HttpClientFeignConfiguration的源碼：
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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(); } }} |
從代碼@ConditionalOnClass({ApacheHttpClient.class})注解可知，只需要在pom文件上加上HttpClient依賴即可。另外需要在配置文件中配置feign.httpclient.enabled為true，從@ConditionalOnProperty注解可知，這個配置可以不寫，因為在默認情況下就為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的源碼：
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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作為網絡請求框架，則只需要在pom文件中加上feign-okhttp的依賴，代碼如下：
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<dependency> <groupId>io.github.openfeign</groupId> <artifactId>feign-okhttp</artifactId> <version>10.2.0</version></dependency> |
OpenFeign替換為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 #單位ms,默認2000 max-connections: 200 #線程池最大連接數 okhttp: enabled: true |
經過上面設置已經可以使用okhttp了，因為在FeignAutoConfiguration中已實現自動裝配
如果需要對okhttp做更精細的參數設置，那需要自定義okhttp的實現，可以模仿上圖中的實現
以上為個人經驗，希望能給大家一個參考，也希望大家多多支持服務器之家。
原文鏈接：https://blog.csdn.net/u010277958/article/details/88730889
