请问哪里出问题了，登录不了

Question

代码：
package pingjia;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.Statement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import javax.swing.ButtonGroup;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPasswordField;
import javax.swing.JRadioButton;
import javax.swing.JTextField;

public class Sql extends JFrame implements ActionListener{
JFrame mm=new JFrame("您好！请您先登录！");
JTextField t2=new JTextField(null,15);
JTextField t4=new JPasswordField(null,15);
public String zh=null;
JRadioButton b=new JRadioButton("学生");
JRadioButton b1=new JRadioButton("督导");
public void jiemian(){
mm.setSize(300,340);
mm.setVisible(true);
mm.setLocation(200,300);
mm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel t1=new JLabel("账号:");
JLabel t3=new JLabel("密码:");
JButton denglu2=new JButton("登录");
denglu2.setContentAreaFilled(false);
Container n=mm.getContentPane();
n.setLayout(null);
t1.setBounds(42,125,75,35);
t2.setBounds(80,125,150,35);
t3.setBounds(40,180,75,35);
t4.setBounds(80,180,150,35);
denglu2.setBounds(102,245,70,30);
n.add(t1);n.add(t2); n.add(t3); n.add(t4); n.add(denglu2);
b.setBounds(130,85,70,30);
b1.setBounds(70,85,70,30);

                ButtonGroup rg=new ButtonGroup(); 
                b.setSelected(false);
                b1.setSelected(true);
                b1.setSelected(false);
                n.add(b);  rg.add(b); n.add(b1); rg.add(b1);
                b.setContentAreaFilled(false);
                b1.setContentAreaFilled(false);

                denglu2.addActionListener(this);
           }

public void actionPerformed(ActionEvent e) {
String driverName="com.microsoft.sqlserver.jdbc.SQLServerDriver";

String dbURL="jdbc:sqlserver://localhost:1433;DatabaseName=pingjia";

String userName="sa";

String userPwd="123456";

 JButton denglu2=(JButton)e.getSource();
if(b.isSelected()) { 
    zh=t2.getText();  
 String mima=t4.getText();

  try {  
        Class.forName(driverName);
        Connection c=DriverManager.getConnection(dbURL,userName,userPwd);
        Statement s=(Statement) c.createStatement(
                ResultSet.TYPE_SCROLL_SENSITIVE,
                ResultSet.CONCUR_UPDATABLE);
                ResultSet r=((java.sql.Statement) s).executeQuery("select * from Student   where Sno='"+zh+"' and Password='"+mima+"'");     
                r.last();       
 if(r.getRow()==1)
 {  mm.setVisible(false);
 r.beforeFirst();
     while(r.next()){  
     JOptionPane.showMessageDialog( null ,r.getString("Sname")+"xuesheng！您好！欢迎登录教师管理系统！" ) ;  }
JFrame mmm=new JFrame();
mmm.setSize(400,420);
mmm.setVisible(true);
mmm.setLocation(200,300);
mmm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel aaa=new JLabel("学生评价模块:");
JButton b1=new JButton("开始评价");b1.setBounds(40,45,140,30);
JButton b10=new JButton("退出系统");b10.setBounds(60,325,100,30);
JButton b11=new JButton("修改密码");b11.setBounds(220,325,100,30);
aaa.setBounds(15,15,90,30); 
Container n=mmm.getContentPane();
    n.setLayout(null);

J_ActionListener1 a1=new J_ActionListener1();

    n.add(b1);n.add(b10);n.add(aaa);

n.add(b11);
b10.addActionListener(new ActionListener()

{ public void actionPerformed(final ActionEvent e)
{ System.exit(0); }
});
((JComponent) mmm.getContentPane()).setOpaque(false);

java.net.URL url = Sql.class.getResource("QQ截图20180628091849.png");
ImageIcon img = new ImageIcon(url);
JLabel background = new JLabel(img);
mmm.getLayeredPane().add(background, new Integer(Integer.MIN_VALUE));
background.setBounds(0, 0, img.getIconWidth(), img.getIconHeight());
}
else{ JOptionPane.showMessageDialog( null ,"账号或密码有误！请重新输入！") ; }
}
catch(Exception e1)
{ e1.printStackTrace(); }
}}
public static void main(String args[]){
Sql app=new Sql();
app.jiemian();

}
}

Answer 1

没必要写那么乱，用分层思想