The server time zone value '???ú±ê×??±??' 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.

    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:127)

这个错误是因为数据库的时区和系统的时区不一致导致的，在数据库连接的url里加上

&serverTimezone=UTC

比如，往后划

private String dbUrl="jdbc:mysql://localhost:3306/db_popr?characterEncoding=utf8&serverTimezone=UTC";
    private String dbUserName="root";
    private String dbPassword="123456";
    private String jdbcName="com.mysql.cj.jdbc.Driver";