"Host 'xxx.xxx.xxx.xx' is blocked because of many connection errors; unblock with 'mysqladmin flush-

错误：java.sql.SQLException 

MESSAGE: null, message from server: "Host 'xxx.xxx.xxx.xx' is blocked because of many connection errors; unblock with 'mysqladmin flush-

1、进入mysql安装目录用mysqladmin命令执行 flush-hosts就搞定了，如在我的linux系统中
/usr/bin/mysqladmin -u root -p  flush-hosts

2、进入mysql：mysql -uroot -pmysql

提高允许的max_connection_errors数量（治标不治本）：

　　① 进入Mysql数据库查看max_connect_errors： show variables like '%max_connect_errors%';

　   ② 修改max_connec_errors的数量为1844674407370954751（能设多大，设多大）： 
set global max_connect_errors = 1844674407370954751;

　　③ 查看是否修改成功：show variables like '%max_connect_errors%';
   show variables like "max_%";