Mon Dec 14 11:33:56 CST 2020 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.
12月14日星期一11:33:56 CST 2020警告：不建议在没有服务器身份验证的情况下建立SSL连接。根据MySQL5.5.45+、5.6.26+和5.7.6+的要求，如果不设置显式选项，则默认必须建立SSL连接。为了符合不使用SSL的现有应用程序，verifyServerCertificate属性设置为“false”。您需要通过设置useSSL=false显式禁用SSL，或者设置useSSL=true并提供用于服务器证书验证的信任库。
解决问题：
Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/mysql01?useUnicode=true&characterEncoding=utf-8&useSSL=false", "root", "root");