注冊载入JDBC驱动程序；
注冊载入驱动driver。也就是强制类载入：其注冊载入JDBC驱动有三种方法：

方法一：Class.forName(DriverName)； 当中DriverName=Driver包名。Driver类名；
Oracle的DriverName=“oracle.jdbc.driver.OracleDriver“。
SQLServer的DriverName=“com.microsoft.jdbc.sqlserver.SQLServerDriver“。
方法三：直接创建一个驱动对象：new oracle.jdbc.driver.OracleDriver()。

MySql的DriverName=“com.mysql.jdbc.Driver“；

方法二：Class.forName(DriverName).newInstance()；

代码完毕两个功能：第一，把驱动程序载入到内存里；第二。把当前载入的驱动程序自己主动去DriverManager那注冊，DriverManager是JDBC规范中唯一的Java类。(Registration is loaded into the JDBC driver.
Registration is loaded into driver driver. That is mandatory class loading: there are three ways to register JDBC drivers.

Method 1: Class.forName (DriverName); among them, the DriverName=Driver package name. Driver class name;
Oracle's DriverName= "oracle.jdbc.driver.OracleDriver".
SQLServer's DriverName= "com.microsoft.jdbc.sqlserver.SQLServerDriver".
Method three: create a driver object directly: new oracle.jdbc.driver.OracleDriver ().

MySql's DriverName= "com.mysql.jdbc.Driver";

Method two: Class.forName (DriverName).NewInstance ();

There are two functions of code completion: first, load the driver into memory; second. Driver Manager is the only Java class in the JDBC specification.)