spring boot下非web应用，mysql数据源报错问题

在非web应用下，spring boot启动时提示如下错误：

org.springframework.context.annotation.AnnotationConfigApplicationContext - Exception encountered during context initialization - cancelling refresh attempt: 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).

spring boot启动时默认会自动配置数据源为org.apache.tomcat.jdbc.pool.DataSource。即使在配置文件或代码中指定了其他的数据源（如druid）。

解决方法是：在@SpringBootApplication注解中取消自动配置，如下：

@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
public class ThisApplication
{
public static void main( String[] args )
{
SpringApplication.run(ThisApplication.class);
}
}

另外，pom.xml中加入依赖：

<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>

有时会出现ClassNotFoundException: com.mysql.jdbc.Driver。并且在IDEA Project Structure ->Modules ->Dependencies中有Maven:mysql:mysql-connector-java:unknown项。

解决在pom.xml指定mysql-connector-java的版本即可