I found how to do manual ack with functional way.
但是，这并没有解释如何在消息之后手动发送确认消息。
如果在确认和发送消息之间有网络错误，我想消息会丢失。
我不想失去消息。
版本

• Spring Boot ：2.7.1
• Spring Cloud：3.2.4

这是我当前的代码

@Controller
class MyFunction(private val myService: MyService) {
    private val objectMapper = ObjectMapper()

    init {
        objectMapper.registerKotlinModule()
    }

    @Bean
    fun function(): (Message<ByteArray>) -> Message<MyResponse> = {
        val channel = it.headers.get(AmqpHeaders.CHANNEL, Channel::class.java)!!
        val deliveryTag = it.headers.get(AmqpHeaders.DELIVERY_TAG, java.lang.Long::class.java)!!.toLong()

        val request = objectMapper.readValue(it.payload, MyRequest::class.java)

        try {
            val response = myService.process(request)

            channel.basicAck(deliveryTag, false)
            // I think it can potentially cause message loss
            MessageBuilder.withPayload(result)
                .build()
        } catch (ex: Exception) {
            channel.basicNack(deliveryTag, false, false)
            throw ex
        }
    }
}