从NetBeans中的mysql数据库中选择特定数据

Question

我在mysql中有一个数据库和表，我想从我的一个表中检索特定行并将其存储到String变量中。 我尝试了如下但未成功

connect c = new connect（）;           连接con = c.start（）;

      PreparedStatement ps = con.prepareStatement("select semester from tfee where semester ='I' ");// I want this **semester asigned to String s1 ;**
      ps.setInt(1, semester.getSelectedIndex());

      ResultSet rs = ps.executeQuery();
      int x =0;
      if(rs.next())
          x=1;
      if (x==1)
  {
      JOptionPane.showMessageDialog(this,"Login Success");
      mainForm m = new mainForm();
      m.setVisible(true);
      dispose();

  }
  else
  {
     JOptionPane.showMessageDialog(this,"Login Fail, Incorrect User ID and/ Password");
  }
      c.stop();
  }
  catch(Exception e)
  {
      JOptionPane.showMessageDialog(this, e);
  }