1
dbc4.MySQLNonTransientConnectionException: Client does not support authentication protocol requested
原因是：客户端不支持服务器请求的身份验证协议； 考虑升级MySQL客户端
查看本地的mysql的版本，看看是不是本地的是8.0结果jar还是5.0的
不一定是升级，降级也是有可能的
2
org.activiti.engine.ActivitiException: couldn't check if tables are already present using metadata:
### Error getting a new connection. Cause: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
org.activiti.engine.ActivitiException：无法使用元数据检查表是否已经存在：
###获取新连接时出错。 原因：com.mysql.jdbc.exceptions.jdbc4.CommunicationsException：通信链接失败
3
Cause: java.sql.SQLException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support
数据库和系统时区差异造成
解决办法：
在jdbc连接的url后面加上serverTimezone=GMT或者UTC参数即可。
4
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.apache.ibatis.reflection.Reflector (file:/G:/Maven/repository/org/mybatis/mybatis/3.2.5/mybatis-3.2.5.jar) to method java.lang.Object.finalize()
WARNING: Please consider reporting this to the maintainers of org.apache.ibatis.reflection.Reflector
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
idea的jdk版本过高，改为1.8即可
5
Fri Jun 12 14:53:55 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.
添加（转义）