配置

建立 WebClient 最簡單的方法是透過以下靜態工廠方法之一：

  • WebClient.create()

  • WebClient.create(String baseUrl)

您還可以使用 WebClient.builder() 配合更多選項：

  • uriBuilderFactory: 用於作為基本 URL 的定製 UriBuilderFactory。

  • defaultUriVariables: 展開 URI 模板時使用的預設值。

  • defaultHeader: 每個請求的請求頭。

  • defaultCookie: 每個請求的 Cookie。

  • defaultApiVersion: 每個請求的 API 版本。

  • defaultRequest: 用於定製每個請求的 Consumer。

  • filter: 每個請求的客戶端過濾器。

  • exchangeStrategies: HTTP 訊息讀取器/寫入器定製。

  • clientConnector: HTTP 客戶端庫設定。

  • apiVersionInserter: 用於在請求中插入 API 版本值。

  • observationRegistry: 用於啟用可觀測性支援的登錄檔。

  • observationConvention: 一個可選的自定義約定，用於提取記錄的可觀測性元資料。

例如：

  • Java

  • Kotlin

WebClient client = WebClient.builder()
		.codecs(configurer -> ... )
		.build();
val webClient = WebClient.builder()
		.codecs { configurer -> ... }
		.build()

一旦構建，WebClient 是不可變的。但是，您可以克隆它並構建一個修改後的副本，如下所示：

  • Java

  • Kotlin

WebClient client1 = WebClient.builder()
		.filter(filterA).filter(filterB).build();

WebClient client2 = client1.mutate()
		.filter(filterC).filter(filterD).build();

// client1 has filterA, filterB

// client2 has filterA, filterB, filterC, filterD
val client1 = WebClient.builder()
		.filter(filterA).filter(filterB).build()

val client2 = client1.mutate()
		.filter(filterC).filter(filterD).build()

// client1 has filterA, filterB

// client2 has filterA, filterB, filterC, filterD

記憶體最大尺寸

為了避免應用程式記憶體問題，編解碼器對記憶體中緩衝資料設定了限制。預設情況下，這些限制設定為 256KB。如果不夠，您將收到以下錯誤：

org.springframework.core.io.buffer.DataBufferLimitException: Exceeded limit on max bytes to buffer

要更改預設編解碼器的限制，請使用以下內容：

  • Java

  • Kotlin

WebClient webClient = WebClient.builder()
		.codecs(configurer -> configurer.defaultCodecs().maxInMemorySize(2 * 1024 * 1024))
		.build();
val webClient = WebClient.builder()
		.codecs { configurer -> configurer.defaultCodecs().maxInMemorySize(2 * 1024 * 1024) }
		.build()

Reactor Netty

要定製 Reactor Netty 設定，請提供一個預配置的 HttpClient：

  • Java

  • Kotlin

HttpClient httpClient = HttpClient.create().secure(sslSpec -> ...);

WebClient webClient = WebClient.builder()
		.clientConnector(new ReactorClientHttpConnector(httpClient))
		.build();
val httpClient = HttpClient.create().secure { ... }

val webClient = WebClient.builder()
	.clientConnector(ReactorClientHttpConnector(httpClient))
	.build()

資源

預設情況下，HttpClient 參與全域性 Reactor Netty 資源（位於 reactor.netty.http.HttpResources），包括事件迴圈執行緒和連線池。這是推薦的模式，因為對於事件迴圈併發，固定、共享的資源是首選。在此模式下，全域性資源在程序退出前一直保持活動狀態。

如果伺服器與程序同時計時，通常不需要顯式關閉。但是，如果伺服器可以在程序內啟動或停止（例如，作為 WAR 部署的 Spring MVC 應用程式），您可以宣告一個 Spring 管理的 ReactorResourceFactory 型別的 bean，並將 globalResources=true（預設值）設定為確保在 Spring ApplicationContext 關閉時關閉 Reactor Netty 全域性資源，如以下示例所示：

  • Java

  • Kotlin

@Bean
public ReactorResourceFactory reactorResourceFactory() {
	return new ReactorResourceFactory();
}
@Bean
fun reactorResourceFactory() = ReactorResourceFactory()

您也可以選擇不參與全域性 Reactor Netty 資源。但是，在此模式下，您需要確保所有 Reactor Netty 客戶端和伺服器例項都使用共享資源，如以下示例所示：

  • Java

  • Kotlin

@Bean
public ReactorResourceFactory resourceFactory() {
	ReactorResourceFactory factory = new ReactorResourceFactory();
	factory.setUseGlobalResources(false); (1)
	return factory;
}

@Bean
public WebClient webClient() {

	Function<HttpClient, HttpClient> mapper = client -> {
		// Further customizations...
	};

	ClientHttpConnector connector =
			new ReactorClientHttpConnector(resourceFactory(), mapper); (2)

	return WebClient.builder().clientConnector(connector).build(); (3)
}
1 建立獨立於全域性資源的資源。
2 使用帶有資源工廠的 ReactorClientHttpConnector 建構函式。
3 將聯結器插入到 WebClient.Builder 中。 
@Bean
fun resourceFactory() = ReactorResourceFactory().apply {
	isUseGlobalResources = false (1)
}

@Bean
fun webClient(): WebClient {

	val mapper: (HttpClient) -> HttpClient = {
		// Further customizations...
	}

	val connector = ReactorClientHttpConnector(resourceFactory(), mapper) (2)

	return WebClient.builder().clientConnector(connector).build() (3)
}
1 建立獨立於全域性資源的資源。
2 使用帶有資源工廠的 ReactorClientHttpConnector 建構函式。
3 將聯結器插入到 WebClient.Builder 中。

超時

配置連線超時：

  • Java

  • Kotlin

import io.netty.channel.ChannelOption;

HttpClient httpClient = HttpClient.create()
		.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 10000);

WebClient webClient = WebClient.builder()
		.clientConnector(new ReactorClientHttpConnector(httpClient))
		.build();
import io.netty.channel.ChannelOption

val httpClient = HttpClient.create()
		.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 10000);

val webClient = WebClient.builder()
		.clientConnector(ReactorClientHttpConnector(httpClient))
		.build();

配置讀取或寫入超時：

  • Java

  • Kotlin

import io.netty.handler.timeout.ReadTimeoutHandler;
import io.netty.handler.timeout.WriteTimeoutHandler;

HttpClient httpClient = HttpClient.create()
		.doOnConnected(conn -> conn
				.addHandlerLast(new ReadTimeoutHandler(10))
				.addHandlerLast(new WriteTimeoutHandler(10)));

// Create WebClient...
import io.netty.handler.timeout.ReadTimeoutHandler
import io.netty.handler.timeout.WriteTimeoutHandler

val httpClient = HttpClient.create()
		.doOnConnected { conn -> conn
				.addHandlerLast(ReadTimeoutHandler(10))
				.addHandlerLast(WriteTimeoutHandler(10))
		}

// Create WebClient...

配置所有請求的響應超時：

  • Java

  • Kotlin

HttpClient httpClient = HttpClient.create()
		.responseTimeout(Duration.ofSeconds(2));

// Create WebClient...
val httpClient = HttpClient.create()
		.responseTimeout(Duration.ofSeconds(2));

// Create WebClient...

配置特定請求的響應超時：

  • Java

  • Kotlin

WebClient.create().get()
		.uri("https://example.org/path")
		.httpRequest(httpRequest -> {
			HttpClientRequest reactorRequest = httpRequest.getNativeRequest();
			reactorRequest.responseTimeout(Duration.ofSeconds(2));
		})
		.retrieve()
		.bodyToMono(String.class);
WebClient.create().get()
		.uri("https://example.org/path")
		.httpRequest { httpRequest: ClientHttpRequest ->
			val reactorRequest = httpRequest.getNativeRequest<HttpClientRequest>()
			reactorRequest.responseTimeout(Duration.ofSeconds(2))
		}
		.retrieve()
		.bodyToMono(String::class.java)

JDK HttpClient

以下示例展示瞭如何定製 JDK HttpClient：

  • Java

  • Kotlin

HttpClient httpClient = HttpClient.newBuilder()
	.followRedirects(Redirect.NORMAL)
	.connectTimeout(Duration.ofSeconds(20))
	.build();

ClientHttpConnector connector =
		new JdkClientHttpConnector(httpClient, new DefaultDataBufferFactory());

WebClient webClient = WebClient.builder().clientConnector(connector).build();
val httpClient = HttpClient.newBuilder()
	.followRedirects(Redirect.NORMAL)
	.connectTimeout(Duration.ofSeconds(20))
	.build()

val connector = JdkClientHttpConnector(httpClient, DefaultDataBufferFactory())

val webClient = WebClient.builder().clientConnector(connector).build()

Jetty

以下示例展示瞭如何定製 Jetty HttpClient 設定：

  • Java

  • Kotlin

HttpClient httpClient = new HttpClient();
httpClient.setCookieStore(...);

WebClient webClient = WebClient.builder()
		.clientConnector(new JettyClientHttpConnector(httpClient))
		.build();
val httpClient = HttpClient()
httpClient.cookieStore = ...

val webClient = WebClient.builder()
		.clientConnector(JettyClientHttpConnector(httpClient))
		.build();

預設情況下，HttpClient 建立自己的資源（Executor、ByteBufferPool、Scheduler），這些資源在程序退出或呼叫 stop() 之前保持活動狀態。

您可以在多個 Jetty 客戶端（和伺服器）例項之間共享資源，並透過宣告一個 Spring 管理的 JettyResourceFactory 型別的 bean 來確保在 Spring ApplicationContext 關閉時關閉資源，如以下示例所示：

  • Java

  • Kotlin

@Bean
public JettyResourceFactory resourceFactory() {
	return new JettyResourceFactory();
}

@Bean
public WebClient webClient() {

	HttpClient httpClient = new HttpClient();
	// Further customizations...

	ClientHttpConnector connector =
			new JettyClientHttpConnector(httpClient, resourceFactory()); (1)

	return WebClient.builder().clientConnector(connector).build(); (2)
}
1 使用帶有資源工廠的 JettyClientHttpConnector 建構函式。
2 將聯結器插入到 WebClient.Builder 中。 
@Bean
fun resourceFactory() = JettyResourceFactory()

@Bean
fun webClient(): WebClient {

	val httpClient = HttpClient()
	// Further customizations...

	val connector = JettyClientHttpConnector(httpClient, resourceFactory()) (1)

	return WebClient.builder().clientConnector(connector).build() (2)
}
1 使用帶有資源工廠的 JettyClientHttpConnector 建構函式。
2 將聯結器插入到 WebClient.Builder 中。

HttpComponents

以下示例展示瞭如何定製 Apache HttpComponents HttpClient 設定：

  • Java

  • Kotlin

HttpAsyncClientBuilder clientBuilder = HttpAsyncClients.custom();
clientBuilder.setDefaultRequestConfig(...);
CloseableHttpAsyncClient client = clientBuilder.build();

ClientHttpConnector connector = new HttpComponentsClientHttpConnector(client);

WebClient webClient = WebClient.builder().clientConnector(connector).build();
val client = HttpAsyncClients.custom().apply {
	setDefaultRequestConfig(...)
}.build()
val connector = HttpComponentsClientHttpConnector(client)
val webClient = WebClient.builder().clientConnector(connector).build()
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