jaxb - org.apache.camel.InvalidPayloadException : No body available of type error thrown while unMarshalling Jaxb Object

Question

我正在通过 Java 将 JAXB 对象发送到 Rabbit MQ。

JAXBContext jaxbContext = JAXBContext.newInstance(MyDTO.class);
    Marshaller jaxbMarshaller = jaxbContext.createMarshaller();

    // output pretty printed
    jaxbMarshaller.setProperty(Marshaller.JAXB_FRAGMENT, true);
     java.io.StringWriter sw = new StringWriter();
     jaxbMarshaller.marshal(deliveryrequest, sw);

    ConnectionFactory factory = new ConnectionFactory() ;

    //TODO change the hardcoding to the properties file
    factory.setHost("rabbitmq.host.net");
    factory.setUsername("user");
    factory.setPassword("pass");
    Channel channel ;
    Connection connection;

    Map<String, Object> args = new HashMap<String, Object>(); 
    String haPolicyValue = "all"; 
    args.put("x-ha-policy", haPolicyValue); 


    connection = factory.newConnection();
    channel = connection.createChannel();
    //TODO change the hardcoding to the properties file
    channel.queueDeclare("upload.com.some.queue", true, false, false, args);
    //TODO change the hardcoding to the properties file
    channel.basicPublish("com.some.exchange", "someroutingKey", 
            new AMQP.BasicProperties.Builder().contentType("text/plain")
            .deliveryMode(2).priority(1).userId("guest").build(),
            sw.toString().getBytes());

我在不同的应用程序中使用 Camel 来阅读这篇文章。

    <camel:route id="myRoute">
        <camel:from uri="RabbitMQEndpoint" />
        <camel:to uri="bean:MyHandler" />
    </camel:route>

处理程序正在使用 Camel 端重做的 Jaxb 对象

 @Handler
 public void handleRequest(MyDTO dto) throws ParseException {

我收到了我没想到的错误。

Caused by: org.apache.camel.NoTypeConversionAvailableException: No type converter available to convert from type: byte[] to the required type: com.mycompany.MyDTO with value [B@1b8d3e42
at org.apache.camel.impl.converter.BaseTypeConverterRegistry.mandatoryConvertTo(BaseTypeConverterRegistry.java:181)
at org.apache.camel.impl.MessageSupport.getMandatoryBody(MessageSupport.java:99)

感谢解决方案。

Answer 1

你从 rabbit 传来的消息体类型是一个 byte[]，你想调用一个 MyDTO 类型的 bean。您的类型不匹配。并且 Camel 找不到可以将消息正文从 byte[] 转换为您的 MyDTO 类型的类型转换器。

Rabbit 的 byte[] 数据是 XML 格式的吗？您是否在 MyDTO 类上有 JAXB 注释，以便您可以使用 JAXB 将其从 xml 编码到 Java？