Unknown character set: 'utf8mb4'

问题描述：com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown character set: 'utf8mb4'

出现问题时使用jar包：mysql-connector-java-5.1.39-bin.jar
修改jar包为：mysql-connector-java-5.1.22-bin.jar
问题解决！