c3p0连接数据库，连接不上，刚开始不走，过了1分钟直接报错

Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception: 
java.sql.SQLNonTransientConnectionException: Public Key Retrieval is not allowed

解决办法：
数据库配置的时候加上jdbc.

jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/spring_jdbc?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8&useSSL=false
jdbc.username=root
jdbc.password=123456