SQLException: No suitable driver found for jdbc:mysql://localhost:3306/xxxx

刚刚学习jsp，对着视频敲代码，报这个错误。
SQLException: No suitable driver found for jdbc:mysql://localhost:3306/shop
SQLState: 08001
VendorError: 0
问题，因为没有引入Driver类。

final String DBDRIVER = "org.gjt.mm.mysql.Driver";
String username = "root";
String password = "root";
String url = "jdbc:mysql://localhost:3306/shop";
Connection con = null;
try {
Class.forName(DBDRIVER);
con = DriverManager.getConnection(url, username, password);
} catch (SQLException e) {
System.out.println("SQLException: " + e.getMessage());
System.out.println("SQLState: " + e.getSQLState());
System.out.println("VendorError: " + e.getErrorCode());
} catch (ClassNotFoundException e) {
System.out.println("Class:" + e.getMessage());
}

加上Class.forName("xxxx")就OK了