为什么 Jackson2JsonMessageConverter 将 List<String> 转换为 List<Object>
Why Jackson2JsonMessageConverter convert List<String> to List<Object>
我正在使用 RabbitMQ 开发 Spring AMQP，我配置了 MessageConverter( Jackson2JsonMessageConverter) 和 ObjectMapper。如果我通过传递 HashMap<String,Object> 从发件人 class 调用 convertAndSend(,,,) 方法，那么 Receiver class handleMessage() 方法成功获得类型 [=22= 的消息] 。但问题是，这个 HashMap 包含一个 List 的字符串作为 List<String> 。当我在 Receiver 中收到此 HashMap 时，我试图通过密钥获取 List<String> 但它给出了错误 List<Object> can't cast Object list to string list 。这是我的代码 Config class ，发送者 class 和接收者 class
@Configuration
public class RabbitMQConfig {
@Autowired
Environment environment;
final static String paymentQueue = "mobily-payment-queue";
final static String mailQueue = "mobily-mail-queue";
final static String orderQueue = "mobily-order-queue";
final static String deductProductQueue = "mobily-deduct-product-queue";
@Bean
public ConnectionFactory connectionFactory() {
CachingConnectionFactory connectionFactory = new CachingConnectionFactory(environment.getRequiredProperty("rabbitmq.host"),Integer.parseInt(environment.getRequiredProperty("rabbitmq.port")));
connectionFactory.setUsername(environment.getRequiredProperty("rabbitmq.user"));
connectionFactory.setPassword(environment.getRequiredProperty("rabbitmq.pass"));
return connectionFactory;
}
@Bean
public MessageConverter jsonMessageConverter() {
final Jackson2JsonMessageConverter converter = new Jackson2JsonMessageConverter();
ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new JodaModule());
mapper.registerModule(new Hibernate4Module());
mapper.setSerializationInclusion(Include.NON_NULL);
converter.setJsonObjectMapper(mapper);
return converter;
}
@Bean
public RabbitTemplate template(MessageConverter jsonMessageConverter) {
RabbitTemplate template = new RabbitTemplate(connectionFactory());
template.setMessageConverter(jsonMessageConverter);
return template;
}
@Bean
public DirectExchange direct() {
return new DirectExchange("mobily.direct");
}
@Bean
public Queue paymentQueue(){
return new Queue(paymentQueue);
}
@Bean
public Queue deductProductQueue() {
return new Queue(deductProductQueue);
}
@Bean
public Queue orderQueue() {
return new Queue(orderQueue);
}
@Bean
public Queue mailQueue(){
return new Queue(mailQueue);
}
@Bean
public Binding paymentBinding(DirectExchange direct, Queue paymentQueue) {
return BindingBuilder.bind(paymentQueue).to(direct).with(environment.getRequiredProperty("rabbitmq.payment.key"));
}
@Bean
public Binding deductProductBinding(DirectExchange direct, Queue deductProductQueue) {
return BindingBuilder.bind(deductProductQueue).to(direct).with(environment.getRequiredProperty("rabbitmq.deduct.product.key"));
}
@Bean
public Binding orderBinding(DirectExchange direct, Queue orderQueue) {
return BindingBuilder.bind(orderQueue).to(direct).with(environment.getRequiredProperty("rabbitmq.order.key"));
}
@Bean
public Binding mailBinding(DirectExchange direct, Queue mailQueue) {
return BindingBuilder.bind(mailQueue).to(direct).with(environment.getRequiredProperty("rabbitmq.mail.key"));
}
/*@Bean
Receiver receiver() {
return new Receiver();
}*/
@Bean
PaymentReceiver paymentReceiver(){
return new PaymentReceiver();
}
@Bean
DeductProductReceiver deductProductReceiver(){
return new DeductProductReceiver();
}
@Bean
OrderReceiver orderReceiver(){
return new OrderReceiver();
}
@Bean
MailReceiver mailReceiver(){
return new MailReceiver();
}
@Bean
SimpleMessageListenerContainer deductProductContainer(ConnectionFactory connectionFactory, MessageListenerAdapter deductProductListenerAdapter) {
SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
container.setConnectionFactory(connectionFactory);
container.setQueueNames(deductProductQueue);
container.setMessageListener(deductProductListenerAdapter);
return container;
}
@Bean
MessageListenerAdapter deductProductListenerAdapter(DeductProductReceiver deductProductReceiver,MessageConverter jsonMessageConverter) {
return new MessageListenerAdapter(deductProductReceiver, jsonMessageConverter);
}
@Bean
SimpleMessageListenerContainer paymentContainer(ConnectionFactory connectionFactory, MessageListenerAdapter paymentListenerAdapter) {
SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
container.setConnectionFactory(connectionFactory);
container.setQueueNames(paymentQueue);
container.setMessageListener(paymentListenerAdapter);
return container;
}
@Bean
MessageListenerAdapter paymentListenerAdapter(PaymentReceiver paymentReceiver,MessageConverter jsonMessageConverter) {
return new MessageListenerAdapter(paymentReceiver,jsonMessageConverter );
}
@Bean
SimpleMessageListenerContainer orderContainer(ConnectionFactory connectionFactory, MessageListenerAdapter orderListenerAdapter) {
SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
container.setConnectionFactory(connectionFactory);
container.setQueueNames(orderQueue);
container.setMessageListener(orderListenerAdapter);
return container;
}
@Bean
MessageListenerAdapter orderListenerAdapter(OrderReceiver orderReceiver,MessageConverter jsonMessageConverter) {
return new MessageListenerAdapter(orderReceiver,jsonMessageConverter);
}
@Bean
SimpleMessageListenerContainer mailContainer(ConnectionFactory connectionFactory, MessageListenerAdapter mailListenerAdapter) {
SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
container.setConnectionFactory(connectionFactory);
container.setQueueNames(mailQueue);
container.setMessageListener(mailListenerAdapter);
return container;
}
@Bean
MessageListenerAdapter mailListenerAdapter(MailReceiver mailReceiver,MessageConverter jsonMessageConverter) {
return new MessageListenerAdapter(mailReceiver,jsonMessageConverter);
}
}
这是我的发件人class
HashMap<String, Object> mailMap=new HashMap<String, Object>();
CustomerAccountUser customerAccountUser=customerAccountUserService.getCustomerAccountUserByUsername(customerAccountPayments.getCustomerName());
ArrayList<String> emailAddress=new ArrayList<String>();
emailAddress.add(customerAccountUser.getEmail());
template.convertAndSend(direct.getName(),environment.getRequiredProperty("rabbitmq.mail.key"),mailMap);
这是我的接收器
public void handleMessage(HashMap<String,Object> mailMap){
try{
System.out.println("mail queue..................................." + mailMap);
String s1=(String)mailMap.get("subject");
String s2=(String)mailMap.get("body");
List<String> list=(List<String>)mailMap.get("emailAddress");
}
}
这是错误
e2016-05-24 17:02:47 ERROR stderr:71 - java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to [Ljava.lang.String;
2016-05-24 17:02:47 ERROR stderr:71 - at com.mobily.service.EmailService.sendEmail(EmailService.java:24)
2016-05-24 17:02:47 INFO stdout:71 - values
2016-05-24 17:02:47 ERROR stderr:71 - at com.mobily.customer.rabbitmq.reciever.MailReceiver.handleMessage(MailReceiver.java:27)
2016-05-24 17:02:47 ERROR stderr:71 - at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
2016-05-24 17:02:47 ERROR stderr:71 - at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
2016-05-24 17:02:47 ERROR stderr:71 - at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
2016-05-24 17:02:47 ERROR stderr:71 - at java.lang.reflect.Method.invoke(Method.java:497)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.util.MethodInvoker.invoke(MethodInvoker.java:269)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.adapter.MessageListenerAdapter.invokeListenerMethod(MessageListenerAdapter.java:387)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.adapter.MessageListenerAdapter.onMessage(MessageListenerAdapter.java:298)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doInvokeListener(AbstractMessageListenerContainer.java:757)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.invokeListener(AbstractMessageListenerContainer.java:680)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.access[=15=]1(SimpleMessageListenerContainer.java:93)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.invokeListener(SimpleMessageListenerContainer.java:183)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.invokeListener(SimpleMessageListenerContainer.java:1358)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.executeListener(AbstractMessageListenerContainer.java:661)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.doReceiveAndExecute(SimpleMessageListenerContainer.java:1102)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.receiveAndExecute(SimpleMessageListenerContainer.java:1086)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.access00(SimpleMessageListenerContainer.java:93)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.run(SimpleMessageListenerContainer.java:1203)`enter code here`e
嗯，很遗憾 Jackson2JsonMessageConverter 不能为你做那件事。
它的逻辑基于三个消息 headers:
public static final String DEFAULT_CLASSID_FIELD_NAME = "__TypeId__";
public static final String DEFAULT_CONTENT_CLASSID_FIELD_NAME = "__ContentTypeId__";
public static final String DEFAULT_KEY_CLASSID_FIELD_NAME = "__KeyTypeId__";
所以，它能做的最好的事情就是 HashMap<Foo, Bar>。但它无法构建正确的嵌套容器类型，因为消息中没有这样的信息 headers.
当然，您必须在 handleMessage 代码的下游做一些进一步的转换（转换）逻辑。我的意思是不转换为 List<String>，而是迭代并转换每个项目。
虽然按照你的发送逻辑：
ArrayList<String> emailAddress=new ArrayList<String>();
emailAddress.add(customerAccountUser.getEmail());
您可以尝试使用 array (String[]) 而不是 List<String>。这应该可以正常工作，因为数组被视为原始类型，而不是容器。
我正在使用 RabbitMQ 开发 Spring AMQP，我配置了 MessageConverter( Jackson2JsonMessageConverter) 和 ObjectMapper。如果我通过传递 HashMap<String,Object> 从发件人 class 调用 convertAndSend(,,,) 方法，那么 Receiver class handleMessage() 方法成功获得类型 [=22= 的消息] 。但问题是，这个 HashMap 包含一个 List 的字符串作为 List<String> 。当我在 Receiver 中收到此 HashMap 时，我试图通过密钥获取 List<String> 但它给出了错误 List<Object> can't cast Object list to string list 。这是我的代码 Config class ，发送者 class 和接收者 class
@Configuration
public class RabbitMQConfig {
@Autowired
Environment environment;
final static String paymentQueue = "mobily-payment-queue";
final static String mailQueue = "mobily-mail-queue";
final static String orderQueue = "mobily-order-queue";
final static String deductProductQueue = "mobily-deduct-product-queue";
@Bean
public ConnectionFactory connectionFactory() {
CachingConnectionFactory connectionFactory = new CachingConnectionFactory(environment.getRequiredProperty("rabbitmq.host"),Integer.parseInt(environment.getRequiredProperty("rabbitmq.port")));
connectionFactory.setUsername(environment.getRequiredProperty("rabbitmq.user"));
connectionFactory.setPassword(environment.getRequiredProperty("rabbitmq.pass"));
return connectionFactory;
}
@Bean
public MessageConverter jsonMessageConverter() {
final Jackson2JsonMessageConverter converter = new Jackson2JsonMessageConverter();
ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new JodaModule());
mapper.registerModule(new Hibernate4Module());
mapper.setSerializationInclusion(Include.NON_NULL);
converter.setJsonObjectMapper(mapper);
return converter;
}
@Bean
public RabbitTemplate template(MessageConverter jsonMessageConverter) {
RabbitTemplate template = new RabbitTemplate(connectionFactory());
template.setMessageConverter(jsonMessageConverter);
return template;
}
@Bean
public DirectExchange direct() {
return new DirectExchange("mobily.direct");
}
@Bean
public Queue paymentQueue(){
return new Queue(paymentQueue);
}
@Bean
public Queue deductProductQueue() {
return new Queue(deductProductQueue);
}
@Bean
public Queue orderQueue() {
return new Queue(orderQueue);
}
@Bean
public Queue mailQueue(){
return new Queue(mailQueue);
}
@Bean
public Binding paymentBinding(DirectExchange direct, Queue paymentQueue) {
return BindingBuilder.bind(paymentQueue).to(direct).with(environment.getRequiredProperty("rabbitmq.payment.key"));
}
@Bean
public Binding deductProductBinding(DirectExchange direct, Queue deductProductQueue) {
return BindingBuilder.bind(deductProductQueue).to(direct).with(environment.getRequiredProperty("rabbitmq.deduct.product.key"));
}
@Bean
public Binding orderBinding(DirectExchange direct, Queue orderQueue) {
return BindingBuilder.bind(orderQueue).to(direct).with(environment.getRequiredProperty("rabbitmq.order.key"));
}
@Bean
public Binding mailBinding(DirectExchange direct, Queue mailQueue) {
return BindingBuilder.bind(mailQueue).to(direct).with(environment.getRequiredProperty("rabbitmq.mail.key"));
}
/*@Bean
Receiver receiver() {
return new Receiver();
}*/
@Bean
PaymentReceiver paymentReceiver(){
return new PaymentReceiver();
}
@Bean
DeductProductReceiver deductProductReceiver(){
return new DeductProductReceiver();
}
@Bean
OrderReceiver orderReceiver(){
return new OrderReceiver();
}
@Bean
MailReceiver mailReceiver(){
return new MailReceiver();
}
@Bean
SimpleMessageListenerContainer deductProductContainer(ConnectionFactory connectionFactory, MessageListenerAdapter deductProductListenerAdapter) {
SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
container.setConnectionFactory(connectionFactory);
container.setQueueNames(deductProductQueue);
container.setMessageListener(deductProductListenerAdapter);
return container;
}
@Bean
MessageListenerAdapter deductProductListenerAdapter(DeductProductReceiver deductProductReceiver,MessageConverter jsonMessageConverter) {
return new MessageListenerAdapter(deductProductReceiver, jsonMessageConverter);
}
@Bean
SimpleMessageListenerContainer paymentContainer(ConnectionFactory connectionFactory, MessageListenerAdapter paymentListenerAdapter) {
SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
container.setConnectionFactory(connectionFactory);
container.setQueueNames(paymentQueue);
container.setMessageListener(paymentListenerAdapter);
return container;
}
@Bean
MessageListenerAdapter paymentListenerAdapter(PaymentReceiver paymentReceiver,MessageConverter jsonMessageConverter) {
return new MessageListenerAdapter(paymentReceiver,jsonMessageConverter );
}
@Bean
SimpleMessageListenerContainer orderContainer(ConnectionFactory connectionFactory, MessageListenerAdapter orderListenerAdapter) {
SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
container.setConnectionFactory(connectionFactory);
container.setQueueNames(orderQueue);
container.setMessageListener(orderListenerAdapter);
return container;
}
@Bean
MessageListenerAdapter orderListenerAdapter(OrderReceiver orderReceiver,MessageConverter jsonMessageConverter) {
return new MessageListenerAdapter(orderReceiver,jsonMessageConverter);
}
@Bean
SimpleMessageListenerContainer mailContainer(ConnectionFactory connectionFactory, MessageListenerAdapter mailListenerAdapter) {
SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
container.setConnectionFactory(connectionFactory);
container.setQueueNames(mailQueue);
container.setMessageListener(mailListenerAdapter);
return container;
}
@Bean
MessageListenerAdapter mailListenerAdapter(MailReceiver mailReceiver,MessageConverter jsonMessageConverter) {
return new MessageListenerAdapter(mailReceiver,jsonMessageConverter);
}
}
这是我的发件人class
HashMap<String, Object> mailMap=new HashMap<String, Object>();
CustomerAccountUser customerAccountUser=customerAccountUserService.getCustomerAccountUserByUsername(customerAccountPayments.getCustomerName());
ArrayList<String> emailAddress=new ArrayList<String>();
emailAddress.add(customerAccountUser.getEmail());
template.convertAndSend(direct.getName(),environment.getRequiredProperty("rabbitmq.mail.key"),mailMap);
这是我的接收器
public void handleMessage(HashMap<String,Object> mailMap){
try{
System.out.println("mail queue..................................." + mailMap);
String s1=(String)mailMap.get("subject");
String s2=(String)mailMap.get("body");
List<String> list=(List<String>)mailMap.get("emailAddress");
}
}
这是错误
e2016-05-24 17:02:47 ERROR stderr:71 - java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to [Ljava.lang.String;
2016-05-24 17:02:47 ERROR stderr:71 - at com.mobily.service.EmailService.sendEmail(EmailService.java:24)
2016-05-24 17:02:47 INFO stdout:71 - values
2016-05-24 17:02:47 ERROR stderr:71 - at com.mobily.customer.rabbitmq.reciever.MailReceiver.handleMessage(MailReceiver.java:27)
2016-05-24 17:02:47 ERROR stderr:71 - at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
2016-05-24 17:02:47 ERROR stderr:71 - at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
2016-05-24 17:02:47 ERROR stderr:71 - at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
2016-05-24 17:02:47 ERROR stderr:71 - at java.lang.reflect.Method.invoke(Method.java:497)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.util.MethodInvoker.invoke(MethodInvoker.java:269)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.adapter.MessageListenerAdapter.invokeListenerMethod(MessageListenerAdapter.java:387)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.adapter.MessageListenerAdapter.onMessage(MessageListenerAdapter.java:298)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doInvokeListener(AbstractMessageListenerContainer.java:757)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.invokeListener(AbstractMessageListenerContainer.java:680)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.access[=15=]1(SimpleMessageListenerContainer.java:93)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.invokeListener(SimpleMessageListenerContainer.java:183)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.invokeListener(SimpleMessageListenerContainer.java:1358)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.executeListener(AbstractMessageListenerContainer.java:661)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.doReceiveAndExecute(SimpleMessageListenerContainer.java:1102)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.receiveAndExecute(SimpleMessageListenerContainer.java:1086)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.access00(SimpleMessageListenerContainer.java:93)
2016-05-24 17:02:47 ERROR stderr:71 - at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.run(SimpleMessageListenerContainer.java:1203)`enter code here`e
嗯，很遗憾 Jackson2JsonMessageConverter 不能为你做那件事。
它的逻辑基于三个消息 headers:
public static final String DEFAULT_CLASSID_FIELD_NAME = "__TypeId__";
public static final String DEFAULT_CONTENT_CLASSID_FIELD_NAME = "__ContentTypeId__";
public static final String DEFAULT_KEY_CLASSID_FIELD_NAME = "__KeyTypeId__";
所以，它能做的最好的事情就是 HashMap<Foo, Bar>。但它无法构建正确的嵌套容器类型，因为消息中没有这样的信息 headers.
当然，您必须在 handleMessage 代码的下游做一些进一步的转换（转换）逻辑。我的意思是不转换为 List<String>，而是迭代并转换每个项目。
虽然按照你的发送逻辑：
ArrayList<String> emailAddress=new ArrayList<String>();
emailAddress.add(customerAccountUser.getEmail());
您可以尝试使用 array (String[]) 而不是 List<String>。这应该可以正常工作，因为数组被视为原始类型，而不是容器。