1. 连单台mongodb

Mongo mg = new Mongo();//默认连本机127.0.0.1 端口为27017
Mongo mg = new Mongo(ip);//可以指定ip 端口默认为27017
Mongo mg = new Mongo(ip,port);//也可以指定ip及端口

2. 连双台mongodb

//ip为主机ip地址，port为端口号，dataBaseName相当于数据库名
DBAddress left = new DBAddress("ip:port/dataBaseName");
DBAddress right = new DBAddress("ip:port/dataBaseName ");
//若一个mongodb出现问题，会自动连另外一台
Mongo mongo = new Mongo(left, right);

3. 连多台mongodb

List<ServerAddress> mongoHost..