如何使用spring反应式webclient将正文发送到消费请求方法?

我必须使用此端点: localhost:5100/message/v1?topic=test.state.v2

此端点需要类似于JSON的主体:

{"topic":"test.state.v2"}

当我用这个cURL测试这个端点时,会正确返回响应数据。

curl -H "Content-Type: application/json" --request GET --data '{"topic": "test.state.v1"}' http://localhost:5100/test/message/v1

我使用此客户端来消费:

public class MyClient {
//imports.. here

private final String dataStoreHostAndPort = "http://localhost:5100";
private finalJSONObject MY_BODY = new JSONObject().put("topic", "test.state.v1");

    public MyClient(WebClient.Builder builder) {
         HttpClient httpClient = HttpClient.create()
                .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 200)
                .followRedirect(true)
                .responseTimeout(Duration.ofMillis(200));
    
        webClient = WebClient.builder()
                .baseUrl(dataStoreHostAndPort)
                .clientConnector(new ReactorClientHttpConnector(httpClient))
                .build();
    }
    
    
    public Mono<String> getMessage() {
        return this.webClient
                .method(HttpMethod.GET)
                .uri(builder -> builder
                        .path("/message/v1")
                        .queryParam("topic", "log.state.v1").build())
                .body((BodyInserter<?, ? super ClientHttpRequest>) MY_BODY)
                .accept(MediaType.APPLICATION_JSON)
                .retrieve()
                .bodyToMono(String.class);
    }

}

我几乎使用了所有形式的 body(BodyInserter) 以及 uri() 但什么都没用。

如何发送 MY_BODY 至弹簧被动 WebClient 以与cURL相同的方式请求?