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)
详细信息如下：
1 F:jdk1.8.0_151injava.exe "-javaagent:E:IntelliJ IDEA 2019.2.1libidea_rt.jar=56252:E:IntelliJ IDEA 2019.2.1in" -Dfile.encoding=UTF-8 -classpath F:jdk1.8.0_151jrelibcharsets.jar;F:jdk1.8.0_151jrelibdeploy.jar;F:jdk1.8.0_151jrelibextaccess-bridge-64.jar;F:jdk1.8.0_151jrelibextcldrdata.jar;F:jdk1.8.0_151jrelibextdnsns.jar;F:jdk1.8.0_151jrelibextjaccess.jar;F:jdk1.8.0_151jrelibextjfxrt.jar;F:jdk1.8.0_151jrelibextlocaledata.jar;F:jdk1.8.0_151jrelibext ashorn.jar;F:jdk1.8.0_151jrelibextsunec.jar;F:jdk1.8.0_151jrelibextsunjce_provider.jar;F:jdk1.8.0_151jrelibextsunmscapi.jar;F:jdk1.8.0_151jrelibextsunpkcs11.jar;F:jdk1.8.0_151jrelibextzipfs.jar;F:jdk1.8.0_151jrelibjavaws.jar;F:jdk1.8.0_151jrelibjce.jar;F:jdk1.8.0_151jrelibjfr.jar;F:jdk1.8.0_151jrelibjfxswt.jar;F:jdk1.8.0_151jrelibjsse.jar;F:jdk1.8.0_151jrelibmanagement-agent.jar;F:jdk1.8.0_151jrelibplugin.jar;F:jdk1.8.0_151jrelib esources.jar;F:jdk1.8.0_151jrelib t.jar;F:workspace abbitmqDemo abbitmqConsumer02 arget est-classes;F: epository_sshorgspringframeworkootspring-boot-starter-logging2.1.0.RELEASEspring-boot-starter-logging-2.1.0.RELEASE.jar;F: epository_sshchqoslogbacklogback-classic1.2.3logback-classic-1.2.3.jar;F: epository_sshchqoslogbacklogback-core1.2.3logback-core-1.2.3.jar;F: epository_sshorgapachelogginglog4jlog4j-to-slf4j2.11.1log4j-to-slf4j-2.11.1.jar;F: epository_sshorgapachelogginglog4jlog4j-api2.11.1log4j-api-2.11.1.jar;F: epository_sshorgslf4jjul-to-slf4j1.7.25jul-to-slf4j-1.7.25.jar;F: epository_sshcom abbitmqamqp-client5.7.0amqp-client-5.7.0.jar;F: epository_sshorgslf4jslf4j-api1.7.26slf4j-api-1.7.26.jar xyfer.Consumer01 2 java.io.IOException 3 at com.rabbitmq.client.impl.AMQChannel.wrap(AMQChannel.java:129) 4 at com.rabbitmq.client.impl.AMQChannel.wrap(AMQChannel.java:125) 5 at com.rabbitmq.client.impl.AMQChannel.exnWrappingRpc(AMQChannel.java:147) 6 at com.rabbitmq.client.impl.ChannelN.exchangeDeclare(ChannelN.java:783) 7 at com.rabbitmq.client.impl.recovery.AutorecoveringChannel.exchangeDeclare(AutorecoveringChannel.java:242) 8 at com.rabbitmq.client.impl.recovery.AutorecoveringChannel.exchangeDeclare(AutorecoveringChannel.java:232) 9 at com.rabbitmq.client.impl.recovery.AutorecoveringChannel.exchangeDeclare(AutorecoveringChannel.java:212) 10 at com.rabbitmq.client.impl.recovery.AutorecoveringChannel.exchangeDeclare(AutorecoveringChannel.java:217) 11 at xyfer.Consumer01.main(Consumer01.java:30) 12 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) 13 at com.rabbitmq.utility.ValueOrException.getValue(ValueOrException.java:66) 14 at com.rabbitmq.utility.BlockingValueOrException.uninterruptibleGetValue(BlockingValueOrException.java:36) 15 at com.rabbitmq.client.impl.AMQChannel$BlockingRpcContinuation.getReply(AMQChannel.java:502) 16 at com.rabbitmq.client.impl.AMQChannel.privateRpc(AMQChannel.java:293) 17 at com.rabbitmq.client.impl.AMQChannel.exnWrappingRpc(AMQChannel.java:141) 18 ... 6 more 19 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) 20 at com.rabbitmq.client.impl.ChannelN.asyncShutdown(ChannelN.java:522) 21 at com.rabbitmq.client.impl.ChannelN.processAsync(ChannelN.java:346) 22 at com.rabbitmq.client.impl.AMQChannel.handleCompleteInboundCommand(AMQChannel.java:182) 23 at com.rabbitmq.client.impl.AMQChannel.handleFrame(AMQChannel.java:114) 24 at com.rabbitmq.client.impl.AMQConnection.readFrame(AMQConnection.java:672) 25 at com.rabbitmq.client.impl.AMQConnection.access$300(AMQConnection.java:48) 26 at com.rabbitmq.client.impl.AMQConnection$MainLoop.run(AMQConnection.java:599) 27 at java.lang.Thread.run(Thread.java:748) 28 29 Process finished with exit code -1
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；
消费端代码如下，交换机名称为“messageChange”，类型为“fanout”；
package xyfer; import com.rabbitmq.client.*; import java.io.IOException; import java.util.concurrent.TimeoutException; public class Consumer02 { //Publish/subscribe发布订阅模式 private static final String QUEUE_SMS ="queueSms"; private static final String EXCHANGE = "messageChange"; 同名 public static void main(String[] args) { Connection connection = null; Channel channel = null; try { ConnectionFactory connectionFactory = new ConnectionFactory(); connectionFactory.setHost("127.0.0.1"); connectionFactory.setPort(5672); connection = connectionFactory.newConnection(); channel = connection.createChannel(); //通道绑定交换机 /** * 参数明细 * 1、交换机名称 * 2、交换机类型，fanout、topic、direct、headers */ //Publish/subscribe发布订阅模式 channel.exchangeDeclare(EXCHANGE, BuiltinExchangeType.FANOUT); 不同类型 //通道绑定队列 /** * 声明队列，如果Rabbit中没有此队列将自动创建 * param1:队列名称 * param2:是否持久化 * param3:队列是否独占此连接 * param4:队列不再使用时是否自动删除此队列 * param5:队列参数 * String queue, boolean durable, boolean exclusive, boolean autoDelete, Map<String, Object> arguments * */ channel.queueDeclare(QUEUE_SMS,true,false,false,null);//通道绑定短信队列 //交换机和队列绑定 /** * 参数明细 * 1、队列名称 * 2、交换机名称 * 3、路由key */ //Publish/subscribe发布订阅模式 channel.queueBind(QUEUE_SMS,EXCHANGE,""); DefaultConsumer consumer = new DefaultConsumer(channel) { /** * 消费者接收消息调用此方法 * @param consumerTag 消费者的标签，在channel.basicConsume()去指定 * @param envelope 消息包的内容，可从中获取消息id，消息routingkey，交换机，消息和重传标志 (收到消息失败后是否需要重新发送) * @param properties * @param body * @throws IOException * String consumerTag, Envelope envelope, BasicProperties properties, byte[] body */ @Override public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException { //交换机 String exchange = envelope.getExchange(); //路由key String routingKey = envelope.getRoutingKey(); envelope.getDeliveryTag(); String msg = new String(body,"utf-8"); System.out.println("mq收到的消息是："+msg ); } }; System.out.println("消费者启动成功！"); channel.basicConsume(QUEUE_SMS,true,consumer); } catch (IOException e) { e.printStackTrace(); } catch (TimeoutException e) { e.printStackTrace(); } } }