java连接oracle No suitable driver found for jdbc:oracle:thin:

代码是按照网上写的：

package hwr.demo.example;



import java.sql.*;



public class ConnectDB {



	public ConnectDB() {

		// TODO Auto-generated constructor stub

	}



	public static void main(String[] args) {

		// TODO Auto-generated method stub

//		DriverManager.registerDriver(new oracle.jdbc.OracleDriver());

	

		try {

			Class.forName("oracle.jdbc.OracleDriver");

		} catch (ClassNotFoundException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		}

		String url = "jdbc:oracle:thin:@localhost:1521:hwr";

		String userName = "scott";

		String password = "tiger";



		try {

//			OracleDataSource dataSource = new OracleDataSource();

			Connection conn = DriverManager.getConnection(url, userName, password);

			Statement stmt = conn.createStatement();

			ResultSet res = stmt.executeQuery("select * from dept");

			while (res.next()){

				System.out.println(res.getString(1));

			}

		

		} catch (SQLException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		}

	}

}

在win7下，oracle10，为什么我在build path已经导入了了classes12.jar文件，也配置了环境变量（C:\oracle\product\10.2.0\db_1\jdbc\lib\classes12.zip;），为什么它还是没有jdbc包的？？？DriverManager.registerDriver(new oracle.jdbc.OracleDriver());这句话会有语法错误，因为oracle.的时候是没有jdbc出现的。而且会出现以下错误：（希望大牛指点）
java.lang.ClassNotFoundException: oracle.jdbc.OracleDriver
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at hwr.demo.example.ConnectDB.main(ConnectDB.java:18)
java.sql.SQLException: No suitable driver found for jdbc:oracle:thin:@localhost:1521:hwr
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at hwr.demo.example.ConnectDB.main(ConnectDB.java:40)