springboot2.0使用rabbit，消费端报错？

Question

@RabbitHandler
    public void  receiverMsg(@Payload String msg,
                             @Headers Map<String,Object> headers,
                             Channel channel) throws Exception{
        // 消费者消费消息
        System.out.println("==========获取消息，开始消费============");
       
        Long deliveryTag = (Long) headers.get(AmqpHeaders.DELIVERY_TAG);// 获取消息序号

        System.out.println("=======消息成功消费，手动触发ack===============");
      
        boolean multiple = false;

        channel.basicAck(deliveryTag,multiple);
    }

Long deliveryTag = (Long) headers.get(AmqpHeaders.DELIVERY_TAG);// 这里提示报错

Caused by: java.lang.ClassCastException: class java.lang.String cannot be cast to class java.lang.Long (java.lang.String and java.lang.Long are in module java.base of loader 'bootstrap')
    at com.gulang.core.rabbitmq.ComsumerMsg.receiverMsg(ComsumerMsg.java:33) ~[classes/:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
    at org.springframework.messaging.handler.invocation.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:171) ~[spring-messaging-5.1.8.RELEASE.jar:5.1.8.RELEASE]
    at org.springframework.messaging.handler.invocation.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:120) ~[spring-messaging-5.1.8.RELEASE.jar:5.1.8.RELEASE]
    at org.springframework.amqp.rabbit.listener.adapter.HandlerAdapter.invoke(HandlerAdapter.java:50) ~[spring-rabbit-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.amqp.rabbit.listener.adapter.MessagingMessageListenerAdapter.invokeHandler(MessagingMessageListenerAdapter.java:196) ~[spring-rabbit-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    ... 26 common frames omitted

Answer 1

试试改成

        Long deliveryTag = Long.parseLong( headers.get(AmqpHeaders.DELIVERY_TAG));// 获取消息序号

返回的就String类型，不能强制转换成Long