`retrieve()`

`retrieve()`方法可用于声明如何提取响应。例如：

Java
Kotlin

WebClient client = WebClient.create("https://example.org");

Mono<ResponseEntity<Person>> result = client.get()
		.uri("/persons/{id}", id).accept(MediaType.APPLICATION_JSON)
		.retrieve()
		.toEntity(Person.class);

val client = WebClient.create("https://example.org")

val result = client.get()
		.uri("/persons/{id}", id).accept(MediaType.APPLICATION_JSON)
		.retrieve()
		.toEntity<Person>().awaitSingle()

或者仅获取主体：

Java
Kotlin

WebClient client = WebClient.create("https://example.org");

Mono<Person> result = client.get()
		.uri("/persons/{id}", id).accept(MediaType.APPLICATION_JSON)
		.retrieve()
		.bodyToMono(Person.class);

val client = WebClient.create("https://example.org")

val result = client.get()
		.uri("/persons/{id}", id).accept(MediaType.APPLICATION_JSON)
		.retrieve()
		.awaitBody<Person>()

要获取已解码对象的流：

Java
Kotlin

Flux<Quote> result = client.get()
		.uri("/quotes").accept(MediaType.TEXT_EVENT_STREAM)
		.retrieve()
		.bodyToFlux(Quote.class);

val result = client.get()
		.uri("/quotes").accept(MediaType.TEXT_EVENT_STREAM)
		.retrieve()
		.bodyToFlow<Quote>()

默认情况下，4xx 或 5xx 响应导致 WebClientResponseException，包含具体 HTTP 状态码的子类。要自定义错误响应的处理方式，请按照以下方式使用 onStatus 处理器：

Java
Kotlin

Mono<Person> result = client.get()
		.uri("/persons/{id}", id).accept(MediaType.APPLICATION_JSON)
		.retrieve()
		.onStatus(HttpStatusCode::is4xxClientError, response -> ...)
		.onStatus(HttpStatusCode::is5xxServerError, response -> ...)
		.bodyToMono(Person.class);

val result = client.get()
		.uri("/persons/{id}", id).accept(MediaType.APPLICATION_JSON)
		.retrieve()
		.onStatus(HttpStatusCode::is4xxClientError) { ... }
		.onStatus(HttpStatusCode::is5xxServerError) { ... }
		.awaitBody<Person>()