使用Spring Boot以来，遇到和解决过好几次不同的项目启动问题，大多数事故起于错误的配置和依赖。因此，本文用于汇总这些问题，以及提供相应的解决方案，帮助大家更快的定位和排除故障。
1. Unregistering JMX-exposed beans on shutdown
项目中没有添加spring-boot-starter-web模块依赖，在启动 Application 运行过程中会出现这个错误。
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v1.5.11.RELEASE)
2018-05-02 18:32:49.445 INFO 33160 --- [ main] cn.mariojd.demo.DemoApplication : Starting DemoApplication on Mario with PID 33160 (started by jd in D:\IntelliJ IDEA\projects\test)
2018-05-02 18:32:49.451 INFO 33160 --- [ main] cn.mariojd.demo.DemoApplication : No active profile set, falling back to default profiles: default
2018-05-02 18:32:49.542 INFO 33160 --- [ main] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@17211155: startup date [Wed May 02 18:32:49 CST 2018]; root of context hierarchy
2018-05-02 18:32:50.115 INFO 33160 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2018-05-02 18:32:50.128 INFO 33160 --- [ main] cn.mariojd.demo.DemoApplication : Started DemoApplication in 1.01 seconds (JVM running for 1.83)
... end SpringApplication.run()
2018-05-02 18:32:50.129 INFO 33160 --- [ Thread-2] s.c.a.AnnotationConfigApplicationContext : Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@17211155: startup date [Wed May 02 18:32:49 CST 2018]; root of context hierarchy
2018-05-02 18:32:50.130 INFO 33160 --- [ Thread-2] o.s.j.e.a.AnnotationMBeanExporter : Unregistering JMX-exposed beans on shutdown
解决方案，引入spring-boot-starter-web模块
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
网上大多数的解决方案是通过添加spring-boot-starter-tomcat依赖来解决，但实测证明此方法不可行。
2. Cannot determine embedded database driver class for database type NONE
项目中添加了spring-boot-starter-data-jpa模块依赖，而且没有配置数据源连接信息的情况下，启动 Application 过程中会出现该错误，原因是Spring Boot在启动时会自动注入数据源和配置JPA。
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v1.5.11.RELEASE)
2018-05-02 19:49:13.640 INFO 37652 --- [ main] cn.mariojd.demo.DemoApplication : Starting DemoApplication on Mario with PID 37652 (started by jd in D:\IntelliJ IDEA\projects\test)
2018-05-02 19:49:13.643 INFO 37652 --- [ main] cn.mariojd.demo.DemoApplication : No active profile set, falling back to default profiles: default
2018-05-02 19:49:13.692 INFO 37652 --- [ main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@62fdb4a6: startup date [Wed May 02 19:49:13 CST 2018]; root of context hierarchy
2018-05-02 19:49:15.150 INFO 37652 --- [ main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration' of type [org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration$$EnhancerBySpringCGLIB$$4ad697b] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2018-05-02 19:49:15.433 INFO 37652 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2018-05-02 19:49:15.460 INFO 37652 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2018-05-02 19:49:15.461 INFO 37652 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.5.29
2018-05-02 19:49:15.564 INFO 37652 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2018-05-02 19:49:15.564 INFO 37652 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 1876 ms
2018-05-02 19:49:15.679 INFO 37652 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean : Mapping servlet: 'dispatcherServlet' to [/]
2018-05-02 19:49:15.682 INFO 37652 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-05-02 19:49:15.682 INFO 37652 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2018-05-02 19:49:15.682 INFO 37652 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2018-05-02 19:49:15.683 INFO 37652 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/*]
2018-05-02 19:49:15.717 WARN 37652 --- [ main] ationConfigEmbeddedWebApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration': Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Tomcat.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Cannot determine embedded database driver class for database type NONE. If you want an embedded database please put a supported one on the classpath. If you have database settings to be loaded from a particular profile you may need to active it (no profiles are currently active).
2018-05-02 19:49:15.719 INFO 37652 --- [ main] o.apache.catalina.core.StandardService : Stopping service [Tomcat]
2018-05-02 19:49:15.765 INFO 37652 --- [ main] utoConfigurationReportLoggingInitializer :
Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.
2018-05-02 19:49:15.791 ERROR 37652 --- [ main] o.s.b.d.LoggingFailureAnalysisReporter :
***************************
APPLICATION FAILED TO START
***************************
Description:
Cannot determine embedded database driver class for database type NONE
Action:
If you want an embedded database please put a supported one on the classpath. If you have database settings to be loaded from a particular profile you may need to active it (no profiles are currently active).
Process finished with exit code 1
- 解决方案1，移除
spring-boot-starter-data-jpa模块依赖； - 解决方案2，将启动类注解
@SpringBootApplication修改如下；
@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class,DataSourceTransactionManagerAutoConfiguration.class, HibernateJpaAutoConfiguration.class})
- 解决方案3，在配置文件中添加数据库连接信息。
spring:
datasource:
url: xxx
username: xxx
password: xxx
