向处理程序添加一个bean id，

@Bean
    public IntegrationFlow sendSms() {
        final ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.configure(MapperFeature.ACCEPT_CASE_INSENSITIVE_PROPERTIES, true);
        final JsonObjectMapper<?, ?> mapper = new Jackson2JsonObjectMapper(objectMapper);
        return IntegrationFlows.from("sendSmsGatewayRequestChannel")
                .handle(Http.outboundGateway(smsEndpoint).expectedResponseType(String.class).httpMethod(HttpMethod.GET)
                        .uriVariableExpressions(createExpressionMap()), **e -> e.id("smsOutboundGateway")**)
                .transform(Transformers.fromJson(SmsResponseDto.class, mapper)).get();
    }

那么你可以模拟响应，

final ArgumentCaptor<Message<?>> messageArgumentCaptor = ArgumentCaptor.forClass(Message.class);
        final MessageHandler mockMessageHandler = MockIntegration.mockMessageHandler(messageArgumentCaptor)
                .handleNextAndReply(m -> MessageBuilder.withPayload(
                        "response")
                        .build());
        mockIntegrationContext.substituteMessageHandlerFor("smsOutboundGateway", mockMessageHandler);

注意：我是Spring集成的新手。所以我不知道这是否是正确的方法。无论如何，它的工作：D。正确，如果我错了。:)

感谢Artem Bilan的帮助。