在一个Tomcat容器中部署了两个springboot的应用，在启动时发现一直都是第一个启动的项目能启动成功，第二个项目启动报错，错误信息如下：
2018-01-30 15:49:27.810 ERROR 7534 --- [ost-startStop-1] o.s.boot.SpringApplication : Application startup failed
org.springframework.jmx.export.UnableToRegisterMBeanException: Unable to register MBean [{
CreateTime:"2018-01-30 15:49:24",
ActiveCount:0,
PoolingCount:0,
CreateCount:0,
DestroyCount:0,
CloseCount:0,
ConnectCount:0,
Connections:[
]
}] with key 'dataSource'; nested exception is javax.management.InstanceAlreadyExistsException: com.alibaba.druid.pool:name=dataSource,type=DruidDataSource
at org.springframework.jmx.export.MBeanExporter.registerBeanNameOrInstance(MBeanExporter.java:628) ~[spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.jmx.export.MBeanExporter.registerBeans(MBeanExporter.java:550) ~[spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.jmx.export.MBeanExporter.afterSingletonsInstantiated(MBeanExporter.java:432) ~[spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:781) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867) ~[spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) ~[spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) ~[spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) ~[spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) ~[spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.boot.web.support.SpringBootServletInitializer.run(SpringBootServletInitializer.java:151) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.boot.web.support.SpringBootServletInitializer.createRootApplicationContext(SpringBootServletInitializer.java:131) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.boot.web.support.SpringBootServletInitializer.onStartup(SpringBootServletInitializer.java:86) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.web.SpringServletContainerInitializer.onStartup(SpringServletContainerInitializer.java:169) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5621) [catalina.jar:7.0.84]
at org.springframework.web.SpringServletContainerInitializer.onStartup(SpringServletContainerInitializer.java:169) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5621) [catalina.jar:7.0.84]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) [catalina.jar:7.0.84]
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:1015) [catalina.jar:7.0.84]
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:991) [catalina.jar:7.0.84]
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:652) [catalina.jar:7.0.84]
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1296) [catalina.jar:7.0.84]
at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:2038) [catalina.jar:7.0.84]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [na:1.7.0_55]
at java.util.concurrent.FutureTask.run(FutureTask.java:262) [na:1.7.0_55]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_55]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [na:1.7.0_55]
at java.lang.Thread.run(Thread.java:745) [na:1.7.0_55]
Caused by: javax.management.InstanceAlreadyExistsException: com.alibaba.druid.pool:name=dataSource,type=DruidDataSource
at com.sun.jmx.mbeanserver.Repository.addMBean(Repository.java:437) ~[na:1.7.0_55]
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerWithRepository(DefaultMBeanServerInterceptor.java:1898) ~[na:1.7.0_55]
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerDynamicMBean(DefaultMBeanServerInterceptor.java:966) ~[na:1.7.0_55]
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerObject(DefaultMBeanServerInterceptor.java:900) ~[na:1.7.0_55]
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:324) ~[na:1.7.0_55]
at com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(JmxMBeanServer.java:522) ~[na:1.7.0_55]
at org.springframework.jmx.support.MBeanRegistrationSupport.doRegister(MBeanRegistrationSupport.java:195) ~[spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.jmx.export.MBeanExporter.registerBeanInstance(MBeanExporter.java:674) ~[spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.jmx.export.MBeanExporter.registerBeanNameOrInstance(MBeanExporter.java:618) ~[spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
... 25 common frames omitted
在网上找到一个类似的帖子，不是一样的报错，不过通过同样的配置方式能解决问题，参考链接：http://blog.csdn.net/licheng989/article/details/72869872
因此在项目的application.yml文件中添加如下配置即可：
- proj01
spring.jmx.default-domain=proj01 - proj02
spring.jmx.default-domain=proj02
配置成不一样的，再启动即可启动成功。