在启动RabbitMQ消费端的时候报错：Caused by: com.rabbitmq.client.ShutdownSignalException: channel error; protocol method: #method<channel.close>(reply-code=406, reply-text=PRECONDITION_FAILED - inequivalent arg 'type' for exchange 'messageChange' in vhost '/': received 'fanout' but current is 'direct', class-id=40, method-id=10)

F:\jdk1.8.0_151\bin\java.exe "-javaagent:E:\IntelliJ IDEA 2019.2.1\lib\idea_rt.jar=58077:E:\IntelliJ IDEA 2019.2.1\bin" -Dfile.encoding=UTF-8 -classpath F:\jdk1.8.0_151\jre\lib\charsets.jar;F:\jdk1.8.0_151\jre\lib\deploy.jar;F:\jdk1.8.0_151\jre\lib\ext\access-bridge-64.jar;F:\jdk1.8.0_151\jre\lib\ext\cldrdata.jar;F:\jdk1.8.0_151\jre\lib\ext\dnsns.jar;F:\jdk1.8.0_151\jre\lib\ext\jaccess.jar;F:\jdk1.8.0_151\jre\lib\ext\jfxrt.jar;F:\jdk1.8.0_151\jre\lib\ext\localedata.jar;F:\jdk1.8.0_151\jre\lib\ext\nashorn.jar;F:\jdk1.8.0_151\jre\lib\ext\sunec.jar;F:\jdk1.8.0_151\jre\lib\ext\sunjce_provider.jar;F:\jdk1.8.0_151\jre\lib\ext\sunmscapi.jar;F:\jdk1.8.0_151\jre\lib\ext\sunpkcs11.jar;F:\jdk1.8.0_151\jre\lib\ext\zipfs.jar;F:\jdk1.8.0_151\jre\lib\javaws.jar;F:\jdk1.8.0_151\jre\lib\jce.jar;F:\jdk1.8.0_151\jre\lib\jfr.jar;F:\jdk1.8.0_151\jre\lib\jfxswt.jar;F:\jdk1.8.0_151\jre\lib\jsse.jar;F:\jdk1.8.0_151\jre\lib\management-agent.jar;F:\jdk1.8.0_151\jre\lib\plugin.jar;F:\jdk1.8.0_151\jre\lib\resources.jar;F:\jdk1.8.0_151\jre\lib\rt.jar;F:\workspace\rabbitmqDemo\rabbitmqConsumer02\target\test-classes;F:\repository_ssh\org\springframework\boot\spring-boot-starter-logging\2.1.0.RELEASE\spring-boot-starter-logging-2.1.0.RELEASE.jar;F:\repository_ssh\ch\qos\logback\logback-classic\1.2.3\logback-classic-1.2.3.jar;F:\repository_ssh\ch\qos\logback\logback-core\1.2.3\logback-core-1.2.3.jar;F:\repository_ssh\org\apache\logging\log4j\log4j-to-slf4j\2.11.1\log4j-to-slf4j-2.11.1.jar;F:\repository_ssh\org\apache\logging\log4j\log4j-api\2.11.1\log4j-api-2.11.1.jar;F:\repository_ssh\org\slf4j\jul-to-slf4j\1.7.25\jul-to-slf4j-1.7.25.jar;F:\repository_ssh\com\rabbitmq\amqp-client\5.7.0\amqp-client-5.7.0.jar;F:\repository_ssh\org\slf4j\slf4j-api\1.7.26\slf4j-api-1.7.26.jar xyfer.Consumer02
java.io.IOException
    at com.rabbitmq.client.impl.AMQChannel.wrap(AMQChannel.java:129)
    at com.rabbitmq.client.impl.AMQChannel.wrap(AMQChannel.java:125)
    at com.rabbitmq.client.impl.AMQChannel.exnWrappingRpc(AMQChannel.java:147)
    at com.rabbitmq.client.impl.ChannelN.exchangeDeclare(ChannelN.java:783)
    at com.rabbitmq.client.impl.recovery.AutorecoveringChannel.exchangeDeclare(AutorecoveringChannel.java:242)
    at com.rabbitmq.client.impl.recovery.AutorecoveringChannel.exchangeDeclare(AutorecoveringChannel.java:232)
    at com.rabbitmq.client.impl.recovery.AutorecoveringChannel.exchangeDeclare(AutorecoveringChannel.java:212)
    at com.rabbitmq.client.impl.recovery.AutorecoveringChannel.exchangeDeclare(AutorecoveringChannel.java:217)
    at xyfer.Consumer02.main(Consumer02.java:28)
Caused by: com.rabbitmq.client.ShutdownSignalException: channel error; protocol method: #method<channel.close>(reply-code=406, reply-text=PRECONDITION_FAILED - inequivalent arg 'type' for exchange 'messageChange' in vhost '/': received 'fanout' but current is 'direct', class-id=40, method-id=10)
    at com.rabbitmq.utility.ValueOrException.getValue(ValueOrException.java:66)
    at com.rabbitmq.utility.BlockingValueOrException.uninterruptibleGetValue(BlockingValueOrException.java:36)
    at com.rabbitmq.client.impl.AMQChannel$BlockingRpcContinuation.getReply(AMQChannel.java:502)
    at com.rabbitmq.client.impl.AMQChannel.privateRpc(AMQChannel.java:293)
    at com.rabbitmq.client.impl.AMQChannel.exnWrappingRpc(AMQChannel.java:141)
    ... 6 more
Caused by: com.rabbitmq.client.ShutdownSignalException: channel error; protocol method: #method<channel.close>(reply-code=406, reply-text=PRECONDITION_FAILED - inequivalent arg 'type' for exchange 'messageChange' in vhost '/': received 'fanout' but current is 'direct', class-id=40, method-id=10)
    at com.rabbitmq.client.impl.ChannelN.asyncShutdown(ChannelN.java:522)
    at com.rabbitmq.client.impl.ChannelN.processAsync(ChannelN.java:346)
    at com.rabbitmq.client.impl.AMQChannel.handleCompleteInboundCommand(AMQChannel.java:182)
    at com.rabbitmq.client.impl.AMQChannel.handleFrame(AMQChannel.java:114)
    at com.rabbitmq.client.impl.AMQConnection.readFrame(AMQConnection.java:672)
    at com.rabbitmq.client.impl.AMQConnection.access$300(AMQConnection.java:48)
    at com.rabbitmq.client.impl.AMQConnection$MainLoop.run(AMQConnection.java:599)
    at java.lang.Thread.run(Thread.java:748)

仔细看一下报错信息：Caused by: com.rabbitmq.client.ShutdownSignalException: channel error; protocol method: #method<channel.close>(reply-code=406, reply-text=PRECONDITION_FAILED - inequivalent arg 'type' for exchange 'messageChange' in vhost '/': received 'fanout' but current is 'direct', class-id=40, method-id=10)

大概意思是交换机的类型不匹配，消费端应该收到名称为“messageChange”，类型为“fanout”的交换机发送的消息，但是当前RabbitMQ中存在的名称为“messageChange”的交换机的类型却是“direct”，所以交换机的类型不匹配。

打开RabbitMQ可以看到确实是这样：

目前有两种解决方式：

一、更改消费端代码中声明的交换机名称即可；

二，把RabbitMQ中的同名却不同类型的交换机删除即可；（测试环境下）