1 描述
- 如果我們直接使用SpringCloud Feign進(jìn)行服務(wù)間調(diào)用的時(shí)候，http組件使用的是JDK的HttpURLConnection，每次請(qǐng)求都會(huì)新建一個(gè)連接，沒(méi)有使用線程池復(fù)用。具體的可以從源碼進(jìn)行分析
2 源碼分析
我們?cè)诜治鲈创a很難找到入口，不知道從何開(kāi)始入手，我們?cè)诜治鯯pringCloud feign的時(shí)候可用在配置文件下面我講一下個(gè)人的思路。
-
1 首先我點(diǎn)擊@EnableFeignClients 看一下這個(gè)注解在哪個(gè)資源路徑下
如下圖所示：
在這里插入圖片描述 -
2 找到服務(wù)啟動(dòng)加載的配置文件
在這里插入圖片描述 - 3 因?yàn)閒eign底層的負(fù)載均衡是基于Ribbon的所以很快就找到了FeignRibbonClientAutoConfiguration.java 這個(gè)類
@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 {
首先我們從這三個(gè)類進(jìn)行分析，從名字上來(lái)看我為了驗(yàn)證沒(méi)有特殊配置，feign底層走的是不是默認(rèn)的DefaultFeignLoadBalancedConfiguration.class
- OkHttpFeignLoadBalancedConfiguration.class
- HttpClientFeignLoadBalancedConfiguration.class
- DefaultFeignLoadBalancedConfiguration.class
DefaultFeignLoadBalancedConfiguration.class
@Configuration
class DefaultFeignLoadBalancedConfiguration {
@Bean
@ConditionalOnMissingBean
public Client feignClient(CachingSpringLoadBalancerFactory cachingFactory,
SpringClientFactory clientFactory) {
return new LoadBalancerFeignClient(new Client.Default(null, null),
cachingFactory, clientFactory);
}
}
從上面代碼可知每次請(qǐng)求過(guò)來(lái)都會(huì)創(chuàng)建一個(gè)新的client,具體的源碼演示有興趣的可以深入研究，在這里不是我們所研究的重點(diǎn)。
OkHttpFeignLoadBalancedConfiguration.class
@Configuration
@ConditionalOnClass(OkHttpClient.class)
@ConditionalOnProperty(value = "feign.okhttp.enabled")
class OkHttpFeignLoadBalancedConfiguration {
@Configuration
@ConditionalOnMissingBean(okhttp3.OkHttpClient.class)
protected static class OkHttpFeignConfiguration {
private okhttp3.OkHttpClient okHttpClient;
@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();
this.okHttpClient = httpClientFactory.createBuilder(httpClientProperties.isDisableSslValidation()).
connectTimeout(connectTimeout, TimeUnit.MILLISECONDS).
followRedirects(followRedirects).
connectionPool(connectionPool).build();
return this.okHttpClient;
}
@PreDestroy
public void destroy() {
if(okHttpClient != null) {
okHttpClient.dispatcher().executorService().shutdown();
okHttpClient.connectionPool().evictAll();
}
}
}
@Bean
@ConditionalOnMissingBean(Client.class)
public Client feignClient(CachingSpringLoadBalancerFactory cachingFactory,
SpringClientFactory clientFactory, okhttp3.OkHttpClient okHttpClient) {
OkHttpClient delegate = new OkHttpClient(okHttpClient);
return new LoadBalancerFeignClient(delegate, cachingFactory, clientFactory);
}
}
從源碼可以看出
- 1 該類是個(gè)配置類，當(dāng)引入OkHttpClient.Class會(huì)加載
- client方法中可以看出會(huì)返回一個(gè)http連接池的client
HttpClientFeignLoadBalancedConfiguration
@Configuration
@ConditionalOnClass(ApacheHttpClient.class)
@ConditionalOnProperty(value = "feign.httpclient.enabled", matchIfMissing = true)
class HttpClientFeignLoadBalancedConfiguration {
這個(gè)類和OkHttpFeignLoadBalancedConfiguration原理類型
使用OKHttp替代默認(rèn)的JDK的HttpURLConnection
- 使用appach httpclient使用教程類似
使用方法
- 1 pom
<dependency>
<groupId>io.github.openfeign</groupId>
<artifactId>feign-okhttp</artifactId>
</dependency>
- 2 Yml文件
feign:
okhttp:
enabled: true
- 3 自定義連接池
可以通過(guò)代碼進(jìn)行配置，也可以通過(guò)yml配置
@Configuration
@ConditionalOnClass(Feign.class)
@AutoConfigureBefore(FeignAutoConfiguration.class)
public class FeignOkHttpConfig {
@Bean
public okhttp3.OkHttpClient okHttpClient(){
return new okhttp3.OkHttpClient.Builder()
.readTimeout(60,TimeUnit.SECONDS)
.connectTimeout(60,TimeUnit.SECONDS)
.connectionPool(new ConnectionPool())
.build();
}
}
驗(yàn)證
-
默認(rèn)的Feign處理會(huì)走到如下位置；
位置處于如下圖所示
在這里插入圖片描述
@Override
public Response execute(Request request, Options options) throws IOException {
HttpURLConnection connection = convertAndSend(request, options);
return convertResponse(connection).toBuilder().request(request).build();
}
-
走okhttp客戶端會(huì)走如下代碼
具體位置如下圖所示：
在這里插入圖片描述
@Override public Response execute() throws IOException {
synchronized (this) {
if (executed) throw new IllegalStateException("Already Executed");
executed = true;
}
captureCallStackTrace();
try {
client.dispatcher().executed(this);
Response result = getResponseWithInterceptorChain();
if (result == null) throw new IOException("Canceled");
return result;
} finally {
client.dispatcher().finished(this);
}
}
驗(yàn)證結(jié)果
如下所示：
5457aa9f869ed2f123267b0077e156c5.png
彩蛋
- okhttp客戶端會(huì)走的代碼可以看出來(lái)okhttp有synchronized鎖線程安全的那默認(rèn)的是否是線程安全的呢 有待去驗(yàn)證。
