SSH整合报错：Could not obtain connection to query metadata

1. Could not obtain connection to query metadata.Connections could not be acquired from the underlying database!

以上问题可能有一下原因造成：
1，驱动配置有误：driver=com.mysql.jdbc.Driver
2，数据库连接地址有误：url=jdbc:mysql://localhost:3306/test?3useUnicode=true&characterEncoding=utf8
3，密码或帐号有误：username=root           password=root
4，数据库未启动或无权访问
5，项目未引入对应的驱动jar包mysql-connector-java-5.x.x-bin.jar
6,mysql root没有远程访问的权限，需要增加权限，增加权限的步骤如下：
进入mysql数据库：
grant all privileges on *.* to 'root'@'%' identified by 'root' with grant option;
flush privileges;