错误现象
javax.management.InstanceNotFoundException: org.springframework.boot:type=Admin,name=SpringApplication
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.getMBean(DefaultMBeanServerInterceptor.java:1095) ~[na:1.8.0_121]
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.getAttribute(DefaultMBeanServerInterceptor.java:643) ~[na:1.8.0_121]
at com.sun.jmx.mbeanserver.JmxMBeanServer.getAttribute(JmxMBeanServer.java:678) ~[na:1.8.0_121]
at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1445) ~[na:1.8.0_121]
at javax.management.remote.rmi.RMIConnectionImpl.access$300(RMIConnectionImpl.java:76) ~[na:1.8.0_121]
at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1309) ~[na:1.8.0_121]
at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1401) ~[na:1.8.0_121]
at javax.management.remote.rmi.RMIConnectionImpl.getAttribute(RMIConnectionImpl.java:639) ~[na:1.8.0_121]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_121]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_121]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:346) ~[na:1.8.0_121]
at sun.rmi.transport.Transport$1.run(Transport.java:200) [na:1.8.0_121]
at sun.rmi.transport.Transport$1.run(Transport.java:197) [na:1.8.0_121]
at java.security.AccessController.doPrivileged(Native Method) [na:1.8.0_121]
at sun.rmi.transport.Transport.serviceCall(Transport.java:196) [na:1.8.0_121]
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:568) [na:1.8.0_121]
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:826) [na:1.8.0_121]
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:683) [na:1.8.0_121]
at java.security.AccessController.doPrivileged(Native Method) [na:1.8.0_121]
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:682) [na:1.8.0_121]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) ~[na:1.8.0_121]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) ~[na:1.8.0_121]
at java.lang.Thread.run(Thread.java:745) ~[na:1.8.0_121]方式一：更改application.properties中的 logging.level.root （我的有效）
将 application.properties 文件中 logging.level.root =debug 里面 debug 改成 info：
#设置日志级别
logging.level.root=info
方式二：在application.properties中添加配置（我的无效）
在springboot中添加配置项：spring.jmx.default-domain= appName
注意：若有效，原因是在一个tomcat服务器下部署了多个采用阿里druid作为数据连接池，结果启动报错。原因是不能在一个tomcat服务器下不能直接部署多个druid作为数据连接池的项目，需要配置
spring.jmx.default-domain=appName方式三：更改 IDEA 配置（我的无效）
