組態

建立 WebClient 最簡單的方式是透過其中一種靜態 Factory 方法

  • WebClient.create()

  • WebClient.create(String baseUrl)

您也可以使用 WebClient.builder() 和更多選項

  • uriBuilderFactory：自訂 UriBuilderFactory 以用作基本 URL。

  • defaultUriVariables：擴充 URI 範本時使用的預設值。

  • defaultHeader：每個請求的標頭。

  • defaultCookie：每個請求的 Cookie。

  • defaultRequest：Consumer 用於自訂每個請求。

  • filter：每個請求的用戶端篩選器。

  • exchangeStrategies：HTTP 訊息讀取器/寫入器自訂。

  • clientConnector：HTTP 用戶端程式庫設定。

  • observationRegistry：用於啟用可觀察性支援的登錄檔。

  • observationConvention：用於提取記錄觀察的元資料的可選自訂慣例。

例如

  • Java

  • Kotlin

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

一旦建立，WebClient 就不可變。 但是，您可以複製它並建立修改後的副本，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

MaxInMemorySize

編解碼器對於記憶體中緩衝資料有限制，以避免應用程式記憶體問題。 預設情況下，這些限制設定為 256KB。 如果這還不夠，您會收到以下錯誤

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

若要變更預設編解碼器的限制，請使用以下程式碼

  • 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

若要自訂 Reactor Netty 設定，請提供預先組態的 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 會參與 reactor.netty.http.HttpResources 中保存的全域 Reactor Netty 資源，包括事件迴圈執行緒和連線池。 這是建議的模式，因為固定、共用的資源是事件迴圈並行的首選。 在此模式下，全域資源會保持活動狀態，直到程序結束。

如果伺服器與程序同步定時，通常不需要明確關閉。 但是，如果伺服器可以在程序內啟動或停止（例如，部署為 WAR 的 Spring MVC 應用程式），您可以宣告類型為 ReactorResourceFactory 且 globalResources=true（預設值）的 Spring 管理的 Bean，以確保在 Spring ApplicationContext 關閉時關閉 Reactor Netty 全域資源，如下列範例所示

  • Java

  • Kotlin

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

您也可以選擇不參與全域 Reactor Netty 資源。 但是，在此模式下，您有責任確保所有 Reactor Netty 用戶端和伺服器實例都使用共用資源，如下列範例所示

  • 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 建立獨立於全域資源的資源。
2 將 ReactorClientHttpConnector 建構子與資源 Factory 搭配使用。
3 將連接器插入 WebClient.Builder。 
@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 建立獨立於全域資源的資源。
2 將 ReactorClientHttpConnector 建構子與資源 Factory 搭配使用。
3 將連接器插入 WebClient.Builder。

逾時

若要組態連線逾時

  • 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();

若要組態讀取或寫入逾時

  • 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...

若要為所有請求組態回應逾時

  • Java

  • Kotlin

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

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

// Create WebClient...

若要為特定請求組態回應逾時

  • 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

以下範例示範如何自訂 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

以下範例示範如何自訂 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 會建立自己的資源（Executor、ByteBufferPool、Scheduler），這些資源會保持活動狀態，直到程序結束或呼叫 stop() 為止。

您可以在 Jetty 用戶端（和伺服器）的多個實例之間共用資源，並透過宣告類型為 JettyResourceFactory 的 Spring 管理的 Bean，確保在 Spring ApplicationContext 關閉時關閉資源，如下列範例所示

  • 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 將 JettyClientHttpConnector 建構子與資源 Factory 搭配使用。
2 將連接器插入 WebClient.Builder。 
@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 將 JettyClientHttpConnector 建構子與資源 Factory 搭配使用。
2 將連接器插入 WebClient.Builder。

HttpComponents

以下範例示範如何自訂 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()