使用java如何实现连接数据库

package com.shsxt.jdbcs;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;public class Demo002JDBCConnect {  public static void main(String[] args) throws ClassNotFoundException {    Class.forName("oracle.jdbc.driver.OracleDriver");    String url = "jdbc:oracle:thin:@localhost:1521:orcl";    String user=  "scott";    String pwd=  "tiger";    Connection conn = null;    Statement s = null;    ResultSet rs = null;    try {      conn = DriverManager.getConnection(url, user, pwd);      s = conn.createStatement();      String sql = "select deptno, dname, loc from dept";      rs = s.executeQuery(sql);      while(rs.next()){        int deptno = rs.getInt(1); // 根据列号来获取值        String dname = rs.getString("dname"); // 根据列名来获取值        String loc = rs.getString(3);        System.out.println(deptno + "\t" + dname + "\t" + loc);      }    } catch (SQLException e) {      e.printStackTrace();    }finally{      if(rs!=null){        try {          rs.close();        } catch (SQLException e) {          // TODO Auto-generated catch block          e.printStackTrace();        }      }      if(s!=null){        try {          s.close();        } catch (SQLException e) {          // TODO Auto-generated catch block          e.printStackTrace();        }      }      if(conn!=null){        try {          conn.close();        } catch (SQLException e) {          // TODO Auto-generated catch block          e.printStackTrace();        }      }    }  }}