如果没有jar驱动包的先到以下连接下载驱动包。

http://download.csdn.net/detail/jxlhc09/6470809

import java.net.UnknownHostException;

import com.mongodb.DB;
import com.mongodb.DBCursor;
import com.mongodb.Mongo;

public class Conn_test {
	public static void main(String[] args) throws UnknownHostException{
		@SuppressWarnings("deprecation")
		Mongo m =new Mongo("192.168.115.24",27017); //ip与端口号
		DB db = m.getDB("admin"); //要连接的数据库
		if(db.authenticate("lhc","lhc".toCharArray())) //用户名与密码
			System.out.println("Success");
		else
			System.out.println("Fail");
		
		String tb = db.getCollectionNames().toString();
		System.out.println(tb);   //打印所有表名
		System.out.println(db.getCollection("system.users").findOne());//打印system.users的第一条记录
		DBCursor dc = db.getCollection("ods_users_dd").find();
		while(dc.hasNext()){
			System.out.println(dc.next()); //输出ods_users_dd的所有记录
		}
	}
}