Wed Jul 25 20:57:47 CST 2018 WARN: 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.

不建议建立没有服务器身份验证的SSL连接。根据MySQL 5.5.45
+、5.626+和5.7.6+的要求,如果没有设置显式选项,默认情况下必须建立SSL连接。对于不使用SSL的现有应用程序,ValuyServer证书属性设置为“false”。您需要通过设置useSSL=
false来显式禁用SSL,或者设置useSSL=真,并为服务器证书验证提供信任存储,
如果仅仅是测试只需要在连接语句后面加上useSSL=false就行了

在配置文件中修改
<property name="jdbcUrl">jdbc:mysql://localhost:3306/yd?useSSL=false<
/property>