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:
- 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:
- @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:
- <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:
- @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:
- <dependency>
- <groupId>io.github.openfeign</groupId>
- <artifactId>feign-okhttp</artifactId>
- <version>10.2.0</version>
- </dependency>