Spring boot 使用mysql

** 开发阶段用 H2即可，上线时，通过以下配置切换到mysql，spring boot将使用这个配置覆盖默认的H2。**

1. 建立数据库：

mysql -u root
CREATE DATABASE springbootdb

2. pom.xml:

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

3. application.properties:

spring.datasource.url= jdbc:mysql://localhost:3306/springbootdb
spring.datasource.username=root
spring.datasource.password=
spring.jpa.hibernate.ddl-auto=create-drop//none, validate, update, create-drop