我正在使用带有JSON消息序列化的RabbitMQ的Spring-boot。使用Direct-Reply-to功能的答复无法在java.util.List
容器内进行我的类。
使用我在Jackson2JsonMessageConverter.fromMessage()
中的调试器,MessageProperties
指出__TypeID__
正确设置为java.util.ArrayList
。但是__ContentTypeId__
是java.lang.Object
是不正确的,因为我期望的是食物(我认为...(。例外消息是: java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to FooDto
请注意,我使用的是Spring-Rabbit 1.7.3而不是V2.0,因此无法将ParameterizedTypeReference
用于rabbitTemplate.convertSendAndReceiveAsType()
方法。
我试图使用DefaultClassMapper
和DefaultJackson2JavaTypeMapper
(在TYPE_ID
和INFERRED
下测试的Typeprecedence(没有成功:
private DefaultJackson2JavaTypeMapper classMapper() {
final DefaultJackson2JavaTypeMapper classMapper = new DefaultJackson2JavaTypeMapper();
final Map<String, Class<?>> idClassMapping = new HashMap<>();
idClassMapping.put(FooDto.class.getSimpleName(), FooDto.class);
classMapper.setIdClassMapping(idClassMapping);
return classMapper;
}
现在的例外是: java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to FooDto
到目前为止,我的解决方法是使用原始类型的数组,即FooDto[]
。
库版本: - 弹簧靴1.5.6 - 兔子:3.7.4 - 弹簧兔1.7.3
maven pom.xml:
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.6.RELEASE</version>
<relativePath />
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.amqp</groupId>
<artifactId>spring-rabbit</artifactId>
</dependency>
</dependencies>
有效POM:
<dependency>
<groupId>org.springframework.amqp</groupId>
<artifactId>spring-amqp</artifactId>
<version>1.7.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.amqp</groupId>
<artifactId>spring-rabbit</artifactId>
<version>1.7.3.RELEASE</version>
</dependency>
RABBITMQ配置:
@Configuration
@EnableRabbit
public class MessagingConfiguration implements ShutdownListener {
// FIXME: List<FooDto> in the direct-reply response contains ArrayList<Object> due to __ContentTypeID__ == SimpleObject/Object . __TypeID__ is correctly ArrayList
@Bean
public List<Declarable> bindings() {
final List<Declarable> declarations = new ArrayList<>();
final FanoutExchange exchange = new FanoutExchange("fx", true, false);
final Queue queue = QueueBuilder.durable("orders").build();
declarations.add(exchange);
declarations.add(queue);
declarations.add(BindingBuilder.bind(queue).to(exchange));
return declarations;
}
// @Bean
// public DefaultClassMapper classMapper() {
// DefaultClassMapper classMapper = new DefaultClassMapper();
// Map<String, Class<?>> idClassMapping = new HashMap<>();
// idClassMapping.put("FooDto", FooDto.class);
// java.util.List<FooDto>
// classMapper.setIdClassMapping(idClassMapping);
// return classMapper;
// }
//
// @Bean
// public DefaultClassMapper classMapper() {
// final DefaultClassMapper typeMapper = new DefaultClassMapper();
// // typeMapper.setDefaultType(new ArrayList<FooDto>().getClass());
// typeMapper.setDefaultType(FooDto[].class);
// return typeMapper;
// }
@Bean
public Jackson2JsonMessageConverter jsonConverter() {
// https://stackoverflow.com/questions/40491628/jackson-configuration-to-consume-list-of-records-in-rabbitmq
// https://github.com/FasterXML/jackson-core/issues/295
final Jackson2JsonMessageConverter converter = new Jackson2JsonMessageConverter();
converter.setTypePrecedence(TypePrecedence.TYPE_ID);
// converter.setClassMapper(classMapper());
return converter;
}
@ConditionalOnProperty(name = "consumer", havingValue = "true")
@Bean
public ConsumerListener listenerConsumer() {
return new ConsumerListener();
}
@ConditionalOnProperty(name = "producer", havingValue = "true")
@Bean
public ProducerListener listenerProducer() {
return new ProducerListener();
}
@Bean
public RabbitAdmin rabbitAdmin(final CachingConnectionFactory connectionFactory) {
return new RabbitAdmin(connectionFactory);
}
@Bean
public SimpleRabbitListenerContainerFactory rabbitListenerContainerFactory(
final ConnectionFactory connectionFactory) {
// Setting the annotation @RabbitListener to use Jackson2JsonMessageConverter
final SimpleRabbitListenerContainerFactory factory = new SimpleRabbitListenerContainerFactory();
factory.setConnectionFactory(connectionFactory);
factory.setMessageConverter(jsonConverter());
factory.setConcurrentConsumers(5);
factory.setMaxConcurrentConsumers(5);
return factory;
}
@Bean
public RabbitTemplate rabbitTemplate(final ConnectionFactory connectionFactory) {
final RabbitTemplate rabbitTemplate = new RabbitTemplate(connectionFactory);
rabbitTemplate.setMessageConverter(jsonConverter()); // convert all sent messages to JSON
rabbitTemplate.setReplyTimeout(TimeUnit.SECONDS.toMillis(3));
rabbitTemplate.setReceiveTimeout(TimeUnit.SECONDS.toMillis(3));
return rabbitTemplate;
}
@Override
public void shutdownCompleted(final ShutdownSignalException arg0) {
}
}
侦听器消耗消息,其中包含来自队列" ordect" from of Exchange" fx"的序列对象:
public class ConsumerListener {
private static final Logger log = LoggerFactory.getLogger(ConsumerListener.class);
@RabbitListener(queues = { "orders" })
public FooDto[] receiveMessage(final MyQuery query) {
log.info(query);
List<FooDto> response = new ArrayList<>();
response.add(new FooDto());
response.add(new FooDto());
response.add(new FooDto());
return response;
}
}
向交易所发送消息时使用的POJO: 类myquery { 私有字符串内容=" test";
public MyQuery();
public String toString() {
return content;
}
}
POJO用于响应: class food to { 私有字符串内容=" foo";
public FooDto();
public String toString() {
return content;
}
}
您的听众有些奇怪;它具有void
的返回类型,但您返回列表。
也就是说,我认为问题是由于类型擦除。
自定义ClassMapper
无济于事,因为那只是顶级课程。
但是,您应该能够构建自定义的Jackson2javatypemapper来创建更复杂的类型。如果没有类映射器,请咨询类型的映射器。请参阅此处。
我现在不在计算机上,但是如果您无法弄清楚,明天我可以看看。
编辑
这是如何自定义转换器的示例...
@SpringBootApplication
public class So49566278Application {
public static void main(String[] args) {
SpringApplication.run(So49566278Application.class, args);
}
@Bean
public ApplicationRunner runner(RabbitTemplate template) {
template.setReplyTimeout(60_000);
return args -> {
@SuppressWarnings("unchecked")
List<Foo> reply = (List<Foo>) template.convertSendAndReceive("so49566278", "baz");
System.out.println(reply);
Foo foo = reply.get(0);
System.out.println(foo);
};
}
@RabbitListener(queues = "so49566278")
public List<Foo> handle(String in) {
return Collections.singletonList(new Foo(in));
}
@Bean
public Queue queue() {
return new Queue("so49566278", false, false, true);
}
@Bean
public MessageConverter converter() {
Jackson2JsonMessageConverter converter = new Jackson2JsonMessageConverter();
converter.setJavaTypeMapper(new DefaultJackson2JavaTypeMapper() {
@Override
public JavaType toJavaType(MessageProperties properties) {
JavaType javaType = super.toJavaType(properties);
if (javaType instanceof CollectionLikeType) {
return TypeFactory.defaultInstance()
.constructCollectionLikeType(List.class, Foo.class);
}
else {
return javaType;
}
}
});
return converter;
}
public static class Foo {
private String bar;
public Foo() {
super();
}
public Foo(String bar) {
this.bar = bar;
}
public String getBar() {
return this.bar;
}
public void setBar(String bar) {
this.bar = bar;
}
@Override
public String toString() {
return "Foo [bar=" + this.bar + "]";
}
}
}
这种方式与无问题的集合一起使用。我认为这很简单:https://stackoverflow.com/a/67130566/10746857