使用ActiveMQ Artemis和Spring Boot“body不可分配给类”

Question

我从Artemis和JMS开始，我有问题得到消息回来。制作者对信息的正确要求；即正确获取和回复。问题是在最后阶段，获取数据。

resp.setJMSType("com.nesdl.flyaway.core.modelmessages.ApplicationsEvent");
log.debug(resp.getJMSType() + " / " + resp.getBody(String.class));
ApplicationsEvent response = resp.getBody(ApplicationsEvent.class);

2021-06-02 09:39:40.060 DEBUG 14288 --- [p-nio-80-exec-1] c.n.f.f.s.ApplicationsServicesImpl       : com.nesdl.flyaway.core.modelmessages.ApplicationsEvent / is null : "{\"applicationsDto\":[{\"id\":1,\"version\":0,\"dateCreated\":\"2021-05-18T17:52:30+0000\",\"dateLastModified\":\"2021-05-18T17:52:30+0000\",\"uuid\":\"66ef5e19-e5ac-48d1-86c8-85d26e0fa205\",\"valid\":true,\"modified\":false,\"toHistorize\":false,\"name\":\"TestApp\",\"description\":\"Première application\"}]}"
2021-06-02 09:39:40.066 DEBUG 14288 --- [p-nio-80-exec-1] o.s.web.servlet.DispatcherServlet        : Failed to complete request: javax.jms.MessageFormatException: Body not assignable to class com.nesdl.flyaway.core.modelmessages.ApplicationsEvent
2021-06-02 09:39:40.071 ERROR 14288 --- [p-nio-80-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is javax.jms.MessageFormatException: Body not assignable to class com.nesdl.flyaway.core.modelmessages.ApplicationsEvent] with root cause

javax.jms.MessageFormatException: Body not assignable to class com.nesdl.flyaway.core.modelmessages.ApplicationsEvent
    at org.apache.activemq.artemis.jms.client.ActiveMQMessage.getBody(ActiveMQMessage.java:740) ~[artemis-jms-client-2.15.0.jar:2.15.0]
    at com.nesdl.flyaway.front.services.ApplicationsServicesImpl.getApplications(ApplicationsServicesImpl.java:52) ~[classes/:na]
    at com.nesdl.flyaway.front.services.ApplicationsServicesImpl$$FastClassBySpringCGLIB$$293cab08.invoke(<generated>) ~[classes/:na]
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.3.6.jar:5.3.6]
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:779) ~[spring-aop-5.3.6.jar:5.3.6]

@Override
public List<ApplicationDto> getApplications() throws IOException, JMSException {
    ApplicationsEvent mess = ApplicationsEvent.builder()
            .applicationsDto(new ArrayList<>())
            .build();
    log.debug("message sent :"+mess.toString());
    Message resp = jmsTemplate.sendAndReceive(JmsSystemConfig.APPLICATIONS_QUEUE, new MessageCreator() {
        @SneakyThrows
        @Override
        public Message createMessage(Session session) throws JMSException {
            Message appMess = session.createTextMessage(objectMapper.writeValueAsString(mess));
            appMess.setStringProperty("_type","com.nesdl.flyaway.core.modelmessages.ApplicationsEvent");
            return appMess;
        }
    });
    resp.setJMSType("com.nesdl.flyaway.core.modelmessages.ApplicationsEvent");
    log.debug(resp.getJMSType() + " / " + resp.getBody(String.class));
    ApplicationsEvent response = resp.getBody(ApplicationsEvent.class);
    log.debug(response.getApplicationsDto().toString());
    return response.getApplicationsDto();
}

我的消费者

@JmsListener(destination = JmsSystemConfig.APPLICATIONS_QUEUE)
public void replyApplications(@Payload ApplicationsEvent appsEvent, @Headers MessageHeaders headers, Message message) throws JMSException, JsonProcessingException {
    ApplicationsEvent resp = ApplicationsEvent.builder()
            .applicationsDto(as.getApplications())
            .build();
    jmsTemplate.convertAndSend(message.getJMSReplyTo(),objectMapper.writeValueAsString(resp));
    log.debug("reply ok "+resp.toString()+" / "+objectMapper.writeValueAsString(resp));
}

和JMS配置

@Configuration
public class JmsConfig {

    @Bean
    public MessageConverter jacksonJmsMessageConverter(ObjectMapper objectMapper) {
        MappingJackson2MessageConverter converter = new MappingJackson2MessageConverter();
        converter.setTargetType(MessageType.TEXT);
        converter.setTypeIdPropertyName("_type");
        converter.setObjectMapper(objectMapper);
        return converter;
    }
}

Answer 1

这里的基本问题是，您发送的是一条文本消息，但您试图使用javax.jms.message.getBody()将其直接分配给com.nesdl.flyaway.core.modelMessages.ApplicationSevent对象，这是行不通的。您必须将文本转换为此对象，就像使用ObjectMapper.WriteValueAsString将此对象转换为文本一样，例如：

ApplicationsEvent response = objectMapper.readValue(resp.getBody(String.class), ApplicationsEvent.class);

此外，这里没有理由调用javax.jms.message.setJMSType()。它本质上什么都不做，所以你只要移除它就很安全了。