Java实现一元二次方程求解器

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
 class SWingConsole{
    public static void run(final JFrame f,final int width,final int height){
        f.setTitle("a * x^2 + b*x + c 运算");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setSize(width, height);
        f.setVisible(true);
    }
}
class Button1 extends JFrame{
    double a,b,c,DT;
    String x1,x2;
    private JButton End = new JButton("结果");
    private JButton Clear = new JButton("清除");
    private JLabel
            label1 = new JLabel ("a:  "),
            label2 = new JLabel ("b:  "),
            label3 = new JLabel ("c:  "),
            label_x1 = new JLabel("x1:  "),
            label_x2 = new JLabel("x2:  ");
    private JTextField 
            text_a = new JTextField(5),
            text_b = new JTextField(5),
            text_c =  new JTextField(5),
            text_x1 =  new JTextField(20),
            text_x2 = new JTextField(20);
    class ButtonListener implements ActionListener{
        public void actionPerformed(ActionEvent e){