技术栈：Spring boot (2.1.5 RELEASE) + Mybatis plus(3.3.1tmp)
本项目想要实现多数据源（引入两个数据库），代码已码完，配置文件都写好了，然后兴致勃勃地启动项目，结果报错，详情请继续往下看：
一、问题描述
简要报错信息如下：
Caused by: org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class
详细报错信息如下：
org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:157) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:142) at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:775) at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) at org.springframework.boot.SpringApplication.run(SpringApplication.java:316) at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260) at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248) at com.uiotsoft.back.brain.platform.MainServer.main(MainServer.java:27) Caused by: org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:125) at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.<init>(TomcatWebServer.java:86) at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getTomcatWebServer(TomcatServletWebServerFactory.java:427) at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getWebServer(TomcatServletWebServerFactory.java:180) at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:181) at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:154) ... 8 common frames omitted Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'securityConfig': Unsatisfied dependency expressed through field 'casProvider'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'casProvider' defined in class path resource [com/uiotsoft/back/brain/platform/config/security/SecurityConfig.class]: Unsatisfied dependency expressed through method 'casAuthenticationProvider' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'customUserDetailsServiceImpl': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userService': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userMapper' defined in file [G:\small_smarthome\2项目代码\trunk\云端\brain-platform(大脑平台)\back-brain-platform(U.AIOT大脑管理平台)\back-brain-platform-infrastructure\target\classes\com\uiotsoft\back\brain\platform\tunnel\database\UserMapper.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [com/baomidou/mybatisplus/autoconfigure/MybatisPlusAutoConfiguration.class]: Unsatisfied dependency expressed through method 'sqlSessionFactory' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/alibaba/druid/spring/boot/autoconfigure/DruidDataSourceAutoConfigure.class]: Invocation of init method failed; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:596) at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:90) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:374) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1411) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:592) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:392) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1321) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1160) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:204) at org.springframework.boot.web.servlet.ServletContextInitializerBeans.getOrderedBeansOfType(ServletContextInitializerBeans.java:235) at org.springframework.boot.web.servlet.ServletContextInitializerBeans.addAsRegistrationBean(ServletContextInitializerBeans.java:193) at org.springframework.boot.web.servlet.ServletContextInitializerBeans.addAsRegistrationBean(ServletContextInitializerBeans.java:188) at org.springframework.boot.web.servlet.ServletContextInitializerBeans.addAdaptableBeans(ServletContextInitializerBeans.java:170) at org.springframework.boot.web.servlet.ServletContextInitializerBeans.<init>(ServletContextInitializerBeans.java:89) at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.getServletContextInitializerBeans(ServletWebServerApplicationContext.java:261) at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.selfInitialize(ServletWebServerApplicationContext.java:234) at org.springframework.boot.web.embedded.tomcat.TomcatStarter.onStartup(TomcatStarter.java:54) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5139) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1377) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1367) at java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:266) at java.util.concurrent.FutureTask.run(FutureTask.java) at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75) at java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:134) at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:902) at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:831) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1377) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1367) at java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:266) at java.util.concurrent.FutureTask.run(FutureTask.java) at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75) at java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:134) at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:902) at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) at org.apache.catalina.core.StandardService.startInternal(StandardService.java:423) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:932) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) at org.apache.catalina.startup.Tomcat.start(Tomcat.java:455) at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:106) ... 13 common frames omitted Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'casProvider' defined in class path resource [com/uiotsoft/back/brain/platform/config/security/SecurityConfig.class]: Unsatisfied dependency expressed through method 'casAuthenticationProvider' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'customUserDetailsServiceImpl': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userService': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userMapper' defined in file [G:\small_smarthome\2项目代码\trunk\云端\brain-platform(大脑平台)\back-brain-platform(U.AIOT大脑管理平台)\back-brain-platform-infrastructure\target\classes\com\uiotsoft\back\brain\platform\tunnel\database\UserMapper.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [com/baomidou/mybatisplus/autoconfigure/MybatisPlusAutoConfiguration.class]: Unsatisfied dependency expressed through method 'sqlSessionFactory' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/alibaba/druid/spring/boot/autoconfigure/DruidDataSourceAutoConfigure.class]: Invocation of init method failed; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:769) at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:509) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1321) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1160) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:277) at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1248) at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1168) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:593) ... 65 common frames omitted Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'customUserDetailsServiceImpl': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userService': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userMapper' defined in file [G:\small_smarthome\2项目代码\trunk\云端\brain-platform(大脑平台)\back-brain-platform(U.AIOT大脑管理平台)\back-brain-platform-infrastructure\target\classes\com\uiotsoft\back\brain\platform\tunnel\database\UserMapper.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [com/baomidou/mybatisplus/autoconfigure/MybatisPlusAutoConfiguration.class]: Unsatisfied dependency expressed through method 'sqlSessionFactory' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/alibaba/druid/spring/boot/autoconfigure/DruidDataSourceAutoConfigure.class]: Invocation of init method failed; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessProperties(CommonAnnotationBeanPostProcessor.java:324) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1411) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:592) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:277) at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1248) at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1168) at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:857) at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:760) ... 78 common frames omitted Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userService': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userMapper' defined in file [G:\small_smarthome\2项目代码\trunk\云端\brain-platform(大脑平台)\back-brain-platform(U.AIOT大脑管理平台)\back-brain-platform-infrastructure\target\classes\com\uiotsoft\back\brain\platform\tunnel\database\UserMapper.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [com/baomidou/mybatisplus/autoconfigure/MybatisPlusAutoConfiguration.class]: Unsatisfied dependency expressed through method 'sqlSessionFactory' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/alibaba/druid/spring/boot/autoconfigure/DruidDataSourceAutoConfigure.class]: Invocation of init method failed; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessProperties(CommonAnnotationBeanPostProcessor.java:324) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1411) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:592) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:204) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.resolveBeanByName(AbstractAutowireCapableBeanFactory.java:452) at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.autowireResource(CommonAnnotationBeanPostProcessor.java:526) at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.getResource(CommonAnnotationBeanPostProcessor.java:496) at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor$ResourceElement.getResourceToInject(CommonAnnotationBeanPostProcessor.java:636) at org.springframework.beans.factory.annotation.InjectionMetadata$InjectedElement.inject(InjectionMetadata.java:180) at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:90) at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessProperties(CommonAnnotationBeanPostProcessor.java:321) ... 90 common frames omitted Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userMapper' defined in file [G:\small_smarthome\2项目代码\trunk\云端\brain-platform(大脑平台)\back-brain-platform(U.AIOT大脑管理平台)\back-brain-platform-infrastructure\target\classes\com\uiotsoft\back\brain\platform\tunnel\database\UserMapper.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [com/baomidou/mybatisplus/autoconfigure/MybatisPlusAutoConfiguration.class]: Unsatisfied dependency expressed through method 'sqlSessionFactory' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/alibaba/druid/spring/boot/autoconfigure/DruidDataSourceAutoConfigure.class]: Invocation of init method failed; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireByType(AbstractAutowireCapableBeanFactory.java:1515) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1395) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:592) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:204) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.resolveBeanByName(AbstractAutowireCapableBeanFactory.java:452) at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.autowireResource(CommonAnnotationBeanPostProcessor.java:526) at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.getResource(CommonAnnotationBeanPostProcessor.java:496) at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor$ResourceElement.getResourceToInject(CommonAnnotationBeanPostProcessor.java:636) at org.springframework.beans.factory.annotation.InjectionMetadata$InjectedElement.inject(InjectionMetadata.java:180) at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:90) at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessProperties(CommonAnnotationBeanPostProcessor.java:321) ... 104 common frames omitted Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [com/baomidou/mybatisplus/autoconfigure/MybatisPlusAutoConfiguration.class]: Unsatisfied dependency expressed through method 'sqlSessionFactory' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/alibaba/druid/spring/boot/autoconfigure/DruidDataSourceAutoConfigure.class]: Invocation of init method failed; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:769) at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:509) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1321) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1160) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:277) at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1248) at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1168) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireByType(AbstractAutowireCapableBeanFactory.java:1500) ... 118 common frames omitted Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/alibaba/druid/spring/boot/autoconfigure/DruidDataSourceAutoConfigure.class]: Invocation of init method failed; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1778) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:593) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:277) at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1248) at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1168) at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:857) at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:760) ... 131 common frames omitted Caused by: org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class at org.springframework.boot.autoconfigure.jdbc.DataSourceProperties.determineDriverClassName(DataSourceProperties.java:236) at org.springframework.boot.autoconfigure.jdbc.DataSourceProperties.determineUsername(DataSourceProperties.java:333) at com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceWrapper.afterPropertiesSet(DruidDataSourceWrapper.java:40) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1837) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1774) ... 142 common frames omitted
二、问题原因
由于使用 Spring Boot 时，默认情况下，配置 DataSource 非常容易。Spring Boot 会自动为我们配置好一个 DataSource。
如果在 application.yml 中指定了 spring.datasource 的相关配置，Spring Boot 就会使用该配置创建一个 DataSource。如果在 application.yml 中没有指定任何 spring.datasource 的相关配置，Spring Boot 会在 classpath 中搜索 H2、hsqldb 等内存数据库的 jar 包，如果找到了，就会自动配置一个内存数据库的 DataSource，所以，我们只要引入 jar 包即可。
而根据报错信息翻译是 “未能确定合适的驱动程序类”，原因是应用没有使用到合适的DataSource，Spring Boot 会自动的为我们配置一个DataSource，而ruidDataSourceAutoConfigure 也会注入一个 DataSourceWrapper，其会在原生的spring.datasource 下找 url, username, password 等，就会导致有两个 DataSource，最后程序就会很郁闷，它也不知道该使用哪个了，所以会报错。
动态数据源 URL 等配置是在 dynamic 下，因此需要排除，否则会报错。
三、解决方案
根据原因分析，解决方案有两种，即排除重复引用的 DataSource，一种是上述配置文件排除，还有一种可以在项目启动类排除：
方式1：配置文件排除
server: port: 8080 spring: datasource: dynamic: primary: db1 # 配置默认数据库 datasource: db1: # 数据源1配置 url: jdbc:mysql://localhost:3306/db1?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=GMT%2B8 username: root password: root driver-class-name: com.mysql.cj.jdbc.Driver db2: # 数据源2配置 url: jdbc:mysql://localhost:3306/db2?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=GMT%2B8 username: root password: root driver-class-name: com.mysql.cj.jdbc.Driver durid: initial-size: 1 max-active: 20 min-idle: 1 max-wait: 60000 autoconfigure: exclude: com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceAutoConfigure # 去除druid配置
autoconfigure: exclude: com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceAutoConfigure # 去除druid配置
方式2：项目启动类排除
@SpringBootApplication(exclude = DruidDataSourceAutoConfigure.class) public class Application { public static void main(String[] args) { SpringApplication.run(Application.class, args); } }
完结！
