1. 复现问题

在Windows上安装好rabbitmq服务(如何在Windows上安装rabbitmq，可以参考该链接：https://blog.csdn.net/lvoelife/article/details/126641514)

使用spring boot - rabbitMq实现消息推送，所有的配置和代码完成后，使用postman发送测试发送消息的接口，如下图所示：

但报出了错误，于是到控制台查看错误信息，如下所示：

com.rabbitmq.client.AuthenticationFailureException: ACCESS_REFUSED - Login was refused using authentication mechanism PLAIN. For details see the broker logfile.
	at com.rabbitmq.client.impl.AMQConnection.start(AMQConnection.java:385) ~[amqp-client-5.14.2.jar:5.14.2]
	at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:1225) ~[amqp-client-5.14.2.jar:5.14.2]
	at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:1173) ~[amqp-client-5.14.2.jar:5.14.2]
	at org.springframework.amqp.rabbit.connection.AbstractConnectionFactory.connectAddresses(AbstractConnectionFactory.java:640) ~[spring-rabbit-2.4.5.jar:2.4.5]
	at org.springframework.amqp.rabbit.connection.AbstractConnectionFactory.connect(AbstractConnectionFactory.java:615) ~[spring-rabbit-2.4.5.jar:2.4.5]
	at org.springframework.amqp.rabbit.connection.AbstractConnectionFactory.createBareConnection(AbstractConnectionFactory.java:565) ~[spring-rabbit-2.4.5.jar:2.4.5]
	at org.springframework.amqp.rabbit.connection.CachingConnectionFactory.createConnection(CachingConnectionFactory.java:725) ~[spring-rabbit-2.4.5.jar:2.4.5]
	at org.springframework.amqp.rabbit.connection.ConnectionFactoryUtils.createConnection(ConnectionFactoryUtils.java:252) ~[spring-rabbit-2.4.5.jar:2.4.5]
	at org.springframework.amqp.rabbit.core.RabbitTemplate.doExecute(RabbitTemplate.java:2173) ~[spring-rabbit-2.4.5.jar:2.4.5]
	at org.springframework.amqp.rabbit.core.RabbitTemplate.execute(RabbitTemplate.java:2146) ~[spring-rabbit-2.4.5.jar:2.4.5]
	at org.springframework.amqp.rabbit.core.RabbitTemplate.send(RabbitTemplate.java:1072) ~[spring-rabbit-2.4.5.jar:2.4.5]
	at org.springframework.amqp.rabbit.core.RabbitTemplate.convertAndSend(RabbitTemplate.java:1137) ~[spring-rabbit-2.4.5.jar:2.4.5]
	at org.springframework.amqp.rabbit.core.RabbitTemplate.convertAndSend(RabbitTemplate.java:1130) ~[spring-rabbit-2.4.5.jar:2.4.5]
	at com.sugon.slowcode.controller.TestController.testSend(TestController.java:30) ~[classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_102]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_102]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_102]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_102]
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-5.3.20.jar:5.3.20]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) ~[spring-web-5.3.20.jar:5.3.20]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:655) ~[tomcat-embed-core-9.0.63.jar:4.0.FR]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.63.jar:4.0.FR]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.20.jar:5.3.20]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.20.jar:5.3.20]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.20.jar:5.3.20]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.20.jar:5.3.20]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.20.jar:5.3.20]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.20.jar:5.3.20]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:360) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:890) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1743) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at java.lang.Thread.run(Thread.java:745) [na:1.8.0_102]

2. 分析问题

分析报错信息中的首句，即 ACCESS_REFUSED - Login was refused using authentication mechanism PLAIN. For details see the broker logfile.。

将其翻译成中文是ACCESS_REFUSED - 使用身份验证机制 PLAIN 拒绝登录。有关详细信息，请参阅代理日志文件。

说白点就是我们链接RabbitMq用户名或密码错误，于是去查看application.properties配置信息和网上资料。

1. 查看application.properties配置信息

spring.rabbitmq.host=127.0.0.1
spring.rabbitmq.port=5672
spring.application.name=demoSpring
spring.rabbitmq.username="guest"
spring.rabbitmq.password="guest"
spring.rabbitmq.publisher-returns=true
spring.rabbitmq.connection-timeout=300000000

配置信息没有问题，因为我使用配置信息中的username和password去登录rabbitmq管理后台，能够正常登录，如下图所示：

2. 查找资料

• 分析guest用户

网上说"guest" user can only connect from localhost即guest用户只被允许从localhost(127.0.0.1)访问。

由于账号guest具有所有的操作权限，并且又是默认账号，出于安全因素的考虑，guest用户只能通过localhost登陆使用，并建议修改guest用户的密码以及新建其他账号管理使用rabbitmq(该功能是在3.3.0版本引入的)。

参考官网文档：https://www.rabbitmq.com/access-control.html

而我配置的就是localhost(127.0.0.1)，所以，guest用户没有问题。

• 新增用户

于是再去查找资料，网上说需要新建用户。

如何新建用户，可以参考这篇博文：新增用户和用户角色权限

用户新增成功后，修改原配置文件username和password信息，其余不变，如下所示：

spring.rabbitmq.username="test"
spring.rabbitmq.password="test123"

重新启动spring boot，再次使用postman调用接口，仍旧报出如上错误。

• 断点分析

如上两种，都无法解决问题，只能依靠打断点来分析。

那么如何打断点？找到上述错误信息第二行，即at com.rabbitmq.client.impl.AMQConnection.start(AMQConnection.java:385) ~[amqp-client-5.14.2.jar:5.14.2]，定位到AMQConnection.java文件的第385行，在此处打个断点，如下图所示：

如上图所示，在AMQConnection.java的346行和347行获取用户名和密码时，出现了问题，因为username = ""guest"",password = ""guest""，分别多一对双引号。

可见，配置文件出现了问题。

3. 解决问题

由上分析可知，配置文件出现问题，应该按照如下修改username和password配置，其余信息不变：

spring.rabbitmq.username=guest
spring.rabbitmq.password=guest

重新启动spirng boot，再次调用测试接口，如下所示：

可以看到，发送消息成功，于是登录rabbitmq的后台管理查看，如下图所示：

4. 总结问题

出现这个问题的原因，一般都是登录rabbitmq的的用户名或密码错误，配置时信息一点即可。