对于最新的稳定版本，请使用 Spring Framework 7.0.6!spring-doc.cadn.net.cn

过滤器

您可以注册一个客户端过滤器 (ExchangeFilterFunction) 通过 WebClient.Builder 以便拦截和修改请求，如下例所示：spring-doc.cadn.net.cn

WebClient client = WebClient.builder()
		.filter((request, next) -> {

			ClientRequest filtered = ClientRequest.from(request)
					.header("foo", "bar")
					.build();

			return next.exchange(filtered);
		})
		.build();
val client = WebClient.builder()
		.filter { request, next ->

			val filtered = ClientRequest.from(request)
					.header("foo", "bar")
					.build()

			next.exchange(filtered)
		}
		.build()

这可以用于横切关注点，例如认证。以下示例使用了一个过滤器通过静态工厂方法进行基本认证：spring-doc.cadn.net.cn

import static org.springframework.web.reactive.function.client.ExchangeFilterFunctions.basicAuthentication;

WebClient client = WebClient.builder()
		.filter(basicAuthentication("user", "password"))
		.build();
import org.springframework.web.reactive.function.client.ExchangeFilterFunctions.basicAuthentication

val client = WebClient.builder()
		.filter(basicAuthentication("user", "password"))
		.build()

可以通过修改现有的 WebClient 实例来添加或删除过滤器，从而生成一个不会影响原始实例的新 WebClient 实例。例如：spring-doc.cadn.net.cn

import static org.springframework.web.reactive.function.client.ExchangeFilterFunctions.basicAuthentication;

WebClient client = webClient.mutate()
		.filters(filterList -> {
			filterList.add(0, basicAuthentication("user", "password"));
		})
		.build();
val client = webClient.mutate()
		.filters { it.add(0, basicAuthentication("user", "password")) }
		.build()

WebClient 是围绕由 ExchangeFunction 跟随的过滤器链的轻量级外观。它提供了一个工作流来处理请求，将请求编码为高级对象以及从高级对象解码，并有助于确保响应内容始终被消耗。当过滤器以某种方式处理响应时，必须特别注意始终消耗其内容，或者以其他方式将其传播到下游的 WebClient，这将确保相同的操作。下面是一个处理 UNAUTHORIZED 状态码的过滤器，但会确保释放任何响应内容，无论是否预期：spring-doc.cadn.net.cn

public ExchangeFilterFunction renewTokenFilter() {
	return (request, next) -> next.exchange(request).flatMap(response -> {
		if (response.statusCode().value() == HttpStatus.UNAUTHORIZED.value()) {
			return response.releaseBody()
					.then(renewToken())
					.flatMap(token -> {
						ClientRequest newRequest = ClientRequest.from(request).build();
						return next.exchange(newRequest);
					});
		} else {
			return Mono.just(response);
		}
	});
}
fun renewTokenFilter(): ExchangeFilterFunction? {
	return ExchangeFilterFunction { request: ClientRequest?, next: ExchangeFunction ->
		next.exchange(request!!).flatMap { response: ClientResponse ->
			if (response.statusCode().value() == HttpStatus.UNAUTHORIZED.value()) {
				return@flatMap response.releaseBody()
						.then(renewToken())
						.flatMap { token: String? ->
							val newRequest = ClientRequest.from(request).build()
							next.exchange(newRequest)
						}
			} else {
				return@flatMap Mono.just(response)
			}
		}
	}
}