根据响应类型处理webclient响应

问题：

如何根据接口返回类型是text/event-stream则逐条返回，否则一次性全部返回？

回答：

使用webclient的toentityflux，而不要使用exchangetomono或exchangetoflux。

WebClient webClient = WebClient.create();

Mono<ResponseEntity<String>> response = webClient.get()
    .uri("http://example.com")
    .retrieve()
    .onStatus(HttpStatusCode::isError, clientResponse -> clientResponse.createException().flatMap(Mono::error))
    .toEntityFlux(String.class)
    .flatMap(responseEntity -> {
        HttpHeaders headers2 = responseEntity.getHeaders();
        MediaType contentType2 = headers2.getContentType();
        if (MediaType.TEXT_EVENT_STREAM.isCompatibleWith(contentType2)) {
            // SSE，逐条返回
            return Mono.just(ResponseEntity.ok()
                .headers(headers2)
                .contentType(MediaType.TEXT_EVENT_STREAM)
                .body(Flux.from(Objects.requireNonNull(responseEntity.getBody()))));
        } else {
            // 非SSE，一次性返回响应体
            return Objects.requireNonNull(responseEntity.getBody()).reduce("", String::concat)
                .map(body2 -> ResponseEntity.ok()
                    .headers(headers2)
                    .body(body2));
        }
    })
    .onErrorResume(WebClientResponseException.class, e -> {
        return Mono.just(ResponseEntity.status(e.getStatusCode())
            .headers(e.getHeaders())
            .body(e.getResponseBodyAsString()));
    })
    .onErrorResume(e -> {
        // 处理其他异常
        HttpHeaders errorHeaders = new HttpHeaders();
        errorHeaders.set("error-status", "500");
        errorHeaders.set("error-message", e.getMessage());
        return Mono.just(ResponseEntity.status(500)
            .headers(errorHeaders)
            .body(Map.of(
                "status", "500",
                "error", "Internal Server Error",
                "message", e.getMessage()
            )));
    });