HTTP 客户端

Spring Boot 提供了多个可用于 HTTP 客户端的 starter。本节解答了与其使用相关的问题。

配置 RestTemplate 使用代理

如 RestTemplate Customization 所述，你可以结合 RestTemplateCustomizer 和 RestTemplateBuilder 来构建自定义的 RestTemplate。这是创建配置代理的 RestTemplate 的推荐方式。

代理配置的具体细节取决于所用的底层客户端请求工厂。

配置基于 Reactor Netty 的 WebClient 所用的 TcpClient

当 classpath 中存在 Reactor Netty 时，会自动配置基于 Reactor Netty 的 WebClient。如需自定义客户端的网络连接处理，可提供 ClientHttpConnector bean。以下示例配置了 60 秒连接超时，并添加了 ReadTimeoutHandler：

Java
Kotlin

import io.netty.channel.ChannelOption;
import io.netty.handler.timeout.ReadTimeoutHandler;
import reactor.netty.http.client.HttpClient;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.ReactorResourceFactory;
import org.springframework.http.client.reactive.ClientHttpConnector;
import org.springframework.http.client.reactive.ReactorClientHttpConnector;

@Configuration(proxyBeanMethods = false)
public class MyReactorNettyClientConfiguration {

	@Bean
	ClientHttpConnector clientHttpConnector(ReactorResourceFactory resourceFactory) {
		HttpClient httpClient = HttpClient.create(resourceFactory.getConnectionProvider())
				.runOn(resourceFactory.getLoopResources())
				.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 60000)
				.doOnConnected((connection) -> connection.addHandlerLast(new ReadTimeoutHandler(60)));
		return new ReactorClientHttpConnector(httpClient);
	}

}

import io.netty.channel.ChannelOption
import io.netty.handler.timeout.ReadTimeoutHandler
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration
import org.springframework.http.client.reactive.ClientHttpConnector
import org.springframework.http.client.reactive.ReactorClientHttpConnector
import org.springframework.http.client.ReactorResourceFactory
import reactor.netty.http.client.HttpClient

@Configuration(proxyBeanMethods = false)
class MyReactorNettyClientConfiguration {

	@Bean
	fun clientHttpConnector(resourceFactory: ReactorResourceFactory): ClientHttpConnector {
		val httpClient = HttpClient.create(resourceFactory.connectionProvider)
			.runOn(resourceFactory.loopResources)
			.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 60000)
			.doOnConnected { connection ->
				connection.addHandlerLast(ReadTimeoutHandler(60))
			}
		return ReactorClientHttpConnector(httpClient)
	}

}

注意 ReactorResourceFactory 的使用，用于连接提供者和事件循环资源。这确保了服务端接收请求与客户端发起请求时资源的高效共享。