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我有这段代码在 Spring Integration 5.0.x / Boot 2.0 下接收 MQTT 消息。它适用于文本消息，但是当我尝试处理二进制消息时它会失败，因为发生转换String并且这会破坏内容（在这种情况下：png 图像文件）。

我怎样才能收到未篡改的消息？

我试着setBytesMessageMapperon DefaultPahoMessageConverter，但这并没有改变任何事情。当我使用 mqtt.fx 下载消息内容时，我可以证明二进制内容设置正确，所以我确信这是接收端的问题。

@Bean
public MessageProducer inbound() {
    MqttPahoMessageDrivenChannelAdapter adapter = new MqttPahoMessageDrivenChannelAdapter("tcp://iot.eclipse.org:1883",
                "foo", "bar");
    adapter.setCompletionTimeout(5000);
    DefaultPahoMessageConverter converter = new DefaultPahoMessageConverter();
    adapter.setConverter(converter);
    adapter.setQos(1);
    adapter.setOutputChannel(mqttInputChannel());
    return adapter;
}
...
@Bean
@ServiceActivator(inputChannel = "mqttInputChannel")
public MessageHandler handler() {
    return new MessageHandler() {

        @Override
        public void handleMessage(Message<?> message) throws MessagingException {
            System.out.println("message received on " + new Date());        
            Object payload = message.getPayload();
            ...
    };
}
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1 回答 1

2

将payloadAsBytes转换器上的属性设置为true...

/**
 * True if the converter should not convert the message payload to a String.
 * Ignored if a {@link BytesMessageMapper} is provided.
 *
 * @param payloadAsBytes The payloadAsBytes to set.
 * @see #setBytesMessageMapper(BytesMessageMapper)
 */
public void setPayloadAsBytes(boolean payloadAsBytes) {
    this.payloadAsBytes = payloadAsBytes;
}
于 2018-03-29T18:34:40.503 回答