原句为
Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.
问题：
不推荐在SSL连接中没有进行服务器身份验证。要么指明不使用SSL，要么使用SSL并提供身份验证。
解决方案
在数据源url后面加上参数 ?useSSL=false
spring.datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://127.0.0.1:3306/myDB?useSSL=false
username: root
password: 123456
