怎样用java连接oracle9i

我把我原来写的代码给你吧.在需要修改的地方我给你注释上

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;

public class connection {

private String DRIVER = "oracle.jdbc.driver.OracleDriver";
private String URL = "jdbc:oracle:thin:@localhost:1521:orcl"; //修改成你自己的
private String USERNAME= "scott"; //你的用户名
private String PWD = "tiger"; //你的密码
private Connection conn = null;
// private Statement stmt = null;

public connection(){
try {
Class.forName(DRIVER);
} catch (ClassNotFoundException e1) {
// TODO Auto-generated catch block
// e1.printStackTrace();
System.out.println("数据驱动加载失败");
}
try{
conn =DriverManager.getConnection(URL,USERNAME,PWD);
}catch(Exception e){
System.out.println("数据库连接失败!");
}
}
public static void