JAVA数据库连接

 String uid=jTextField.getText();
 String upass=jTextField.getText();
 try {
      Class.forName("oracle.jdbc.driver.OracleDriver");//要导入外部包
      Connection conn=DriverManager.getConnection("jdbc:oracle:thin:scott/tiger@localhost:1522:stuf1dbsid");//最后一个是oracle的sid号
stuf1dbsid  sid号 scott/tiger登陆 sql为sql命令串 logondb为表 表有userid upass
                     //  sql句子  为  select * from logindb where userid='uid' and upass='upass'   ""不显示 ''才显示 ''是sql语句中框变量的
      String sql="select * from logindb where userid='" + uid + "'and  upass='" + upass+ "'";
//  定义result
      PreparedStatement psmt= conn.prepareStatement(sql);
      ResultSet res = psmt.executeQuery();
      if(res.next())
      {
       TestDia t= new TestDia(null);
       t.setVisible(true);
      }else
      {
       System.out.println("login error");
      }
     } catch (ClassNotFoundException e1) {
      
      e1.printStackTrace();
     }
    
     catch (SQLException e1) {
      
      e1.printStackTrace();
     }
 try {
   Class.forName("oracle.jdbc.driver.OracleDriver");
   Connection conn=DriverManager.ge