This similar problem has been encountered several times, but you can still find the error every time you report an error. When reporting an error, think about what you modified earlier, and then go to see if the corresponding code has the same path. Or attribute problems. But I can’t find the error report this time. The previous version before my modification can still be started. When I came to work the next day, I reported an error as soon as it was started. It has not been solved yet. If it is solved, the answer will be pasted. The following error reasons:

Code text:

01-Dec-2021 18:58:11.804 信息 [RMI TCP Connection(3)-127.0.0.1] org.apache.catalina.core.ApplicationContext.log Spring WebApplicationInitializers detected on classpath: [org.springframework.boot.autoconfigure.jersey.JerseyAutoConfiguration$JerseyWebApplicationInitializer@b0ebd27]
01-Dec-2021 18:58:11.953 信息 [RMI TCP Connection(3)-127.0.0.1] org.apache.catalina.core.ApplicationContext.log Initializing Spring root WebApplicationContext
01-Dec-2021 18:58:15.892 严重 [RMI TCP Connection(3)-127.0.0.1] org.apache.catalina.core.StandardContext.listenerStart 异常将上下文初始化事件发送到类的侦听器实例.[org.springframework.web.context.ContextLoaderListener]
		at org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager.preparePersistenceUnitInfos(DefaultPersistenceUnitManager.java:470)
		at org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager.afterPropertiesSet(DefaultPersistenceUnitManager.java:424)
		at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:310)
		at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:319)
		at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637)
		at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574)
		... 59 more
01-Dec-2021 18:58:15.911 信息 [RMI TCP Connection(3)-127.0.0.1] org.apache.catalina.core.ApplicationContext.log Closing Spring root WebApplicationContext
	org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'emf' defined in org.ngrinder.infra.config.DatabaseConfig: Invocation of init method failed; nested exception is java.lang.IllegalStateException: Conflicting persistence unit definitions for name 'ngrinder': file:/D:/zaixianStudy/0server/apache-tomcat-8.5.69/webapps/ngrinder-web/WEB-INF/lib/ngrinder-controller-3.4.4.jar, file:/D:/zaixianStudy/0server/apache-tomcat-8.5.69/webapps/ngrinder-web/WEB-INF/classes
		at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1578)
		at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545)
		at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
		at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
		at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
		at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
		at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
		at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1054)
		at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:829)
		at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:538)
		at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:444)
		at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:326)
		at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:107)
		at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4763)
		at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5232)
		at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
		at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:755)
		at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:729)
		at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:695)
		at org.apache.catalina.startup.HostConfig.manageApp(HostConfig.java:1775)
		at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
		at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
		at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
		at java.lang.reflect.Method.invoke(Method.java:498)
		at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:291)
		at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
		at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
		at org.apache.catalina.mbeans.MBeanFactory.createStandardContext(MBeanFactory.java:483)
		at org.apache.catalina.mbeans.MBeanFactory.createStandardContext(MBeanFactory.java:431)
		at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
		at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
		at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
		at java.lang.reflect.Method.invoke(Method.java:498)
		at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:291)
		at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
		at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
		at com.sun.jmx.remote.security.MBeanServerAccessController.invoke(MBeanServerAccessController.java:468)
		at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1468)
		at javax.management.remote.rmi.RMIConnectionImpl.access$300(RMIConnectionImpl.java:76)
		at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1309)
		at java.security.AccessController.doPrivileged(Native Method)
		at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1408)
		at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:829)
		at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
		at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
		at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
		at java.lang.reflect.Method.invoke(Method.java:498)
		at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:357)
		at sun.rmi.transport.Transport$1.run(Transport.java:200)
		at sun.rmi.transport.Transport$1.run(Transport.java:197)
		at java.security.AccessController.doPrivileged(Native Method)
		at sun.rmi.transport.Transport.serviceCall(Transport.java:196)
		at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:568)
		at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:826)
		at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:683)
		at java.security.AccessController.doPrivileged(Native Method)
		at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:682)
		at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
		at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
		at java.lang.Thread.run(Thread.java:748)
	Caused by: java.lang.IllegalStateException: Conflicting persistence unit definitions for name 'ngrinder': file:/D:/zaixianStudy/0server/apache-tomcat-8.5.69/webapps/ngrinder-web/WEB-INF/lib/ngrinder-controller-3.4.4.jar, file:/D:/zaixianStudy/0server/apache-tomcat-8.5.69/webapps/ngrinder-web/WEB-INF/classes

The problem has been solved. Let’s talk about my handling method. I won’t talk about bullshit. I’ve met those interfaces with the same URL, no annotation, the same method name, wrong package, different versions, repeated POM files or inconsistent versions, and what reset projects empty Maven and download again. I’ve met them many times, I’ve tried it all. The answers on the Internet are the same, copy around. My situation is like this. I can run on the first day, but I can’t do it on the second day. I don’t have a clue about the error reported. I checked the GIT code again and again and found that there is nothing wrong and I can’t start. So I did the following work:

1. Find the local tomcat, delete the jar package in webapp and the compiled project file, delete the Tomcat configuration in the project, and reconfigure it

2. Check whether Maven is configured correctly, whether Maven is its own, whether the settings.xml file is correct, and the warehouse. There are many local versions of tomcat, Maven and JDK. I downloaded a lot to test the difference between versions before. After checking, click the navigation bar on the right, circle, refresh and brush several times

3. Click File >>>> ProjectStructure>>> Modules, delete all and reintroduce

4. Check whether the artifacts are correct, and there must be all of them

5. On the right navigation bar, refresh maven, clear, complex, package and run, which solves my problem.

The above is my solution. I have no problem with the code. If there is a problem with the code, don’t use it