问题：
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Public Key Retrieval is not allowed
处理(jdbcurl链接串上加allowPublicKeyRetrieval=true) 例：
jdbc:mysql://127.0.0.1:3306/tsingyun_iot_platform?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai&useSSL=false&allowPublicKeyRetrieval=true
