`retrieve()`

retrieve() 方法可用於宣告如何提取響應。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()

或者只獲取正文：

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>()

要獲取解碼物件的流：

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>()

預設情況下，4xx 或 5xx 響應會導致 WebClientResponseException，包括特定 HTTP 狀態碼的子類。要自定義錯誤響應的處理，請使用 onStatus 處理器，如下所示：

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>()