我的程序中出现以下错误：
run:
Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: -1
at java.util.Vector.elementData(Vector.java:730)
at java.util.Vector.elementAt(Vector.java:473)
at javax.swing.DefaultListModel.elementAt(DefaultListModel.java:266)
at bfpl.BFPL$1$2$13.actionPerformed(BFPL.java:851)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6505)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
at java.awt.Component.processEvent(Component.java:6270)
at java.awt.Container.processEvent(Container.java:2229)
at java.awt.Component.dispatchEventImpl(Component.java:4861)
at java.awt.Container.dispatchEventImpl(Container.java:2287)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
at java.awt.Container.dispatchEventImpl(Container.java:2273)
at java.awt.Window.dispatchEventImpl(Window.java:2719)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:723)
at java.awt.EventQueue.access$200(EventQueue.java:103)
at java.awt.EventQueue$3.run(EventQueue.java:682)
at java.awt.EventQueue$3.run(EventQueue.java:680)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
at java.awt.EventQueue$4.run(EventQueue.java:696)
at java.awt.EventQueue$4.run(EventQueue.java:694)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:693)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)
我的代码是：
final JFrame f8=new JFrame("New Schedule");
f8.setVisible(true);
f3.setVisible(false);
f8.setSize(1000,1000);
f8.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JPanel p8=new JPanel(new GridBagLayout());
GridBagConstraints g8=new GridBagConstraints();
g8.insets=new Insets(2,2,2,2);
JButton b21=new JButton("Back");
JButton b22=new JButton("Save");
JLabel l40=new JLabel("Match No");
JLabel l41=new JLabel("Home Team");
JLabel l42=new JLabel("Away Team");
JLabel l43=new JLabel("Stadium");
JLabel l44=new JLabel("Date");
JLabel l45=new JLabel("mm/dd/yyyy");
JLabel l56=new JLabel("City");
final JTextField t38=new JTextField(15);
JTextField t39=new JTextField(15);
DefaultListModel dl1=new DefaultListModel();
DefaultListModel dl2=new DefaultListModel();
DefaultListModel dl3=new DefaultListModel();
DefaultListModel dl9=new DefaultListModel();
String query1="Select Stadium,Location from Stadiums";
try{
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException ex) {
Logger.getLogger(BFPL.class.getName()).log(Level.SEVERE, null, ex);
}
Connection con1=DriverManager.getConnection("jdbc:mysql://127.0.0.1/BFPL","root","ilovepepsi");
Statement stm=(Statement) con1.createStatement();
ResultSet rs=stm.executeQuery(query1);
while(rs.next()){
String std=rs.getString("Stadium");
String std1=rs.getString("Location");
dl1.addElement(std);
dl9.addElement(std1);
}
}
catch(SQLException ae){
System.out.println("SQLException:"+ae.getMessage());
System.out.println("SQLState:"+ae.getSQLState());
System.out.println("VendorError:"+ae.getErrorCode());
JOptionPane.showMessageDialog(p8,"Error in submitting data!");
}
String query2="Select Team_Name from Team";
try{
Connection con2=DriverManager.getConnection("jdbc:mysql://127.0.0.1/BFPL","root","ilovepepsi");
Statement stm1=con2.createStatement();
ResultSet rs1=stm1.executeQuery(query2);
while(rs1.next()){
String t=rs1.getString("Team_Name");
dl2.addElement(t);
dl3.addElement(t);
}
}
catch(SQLException ae){
System.out.println("SQLException:"+ae.getMessage());
System.out.println("SQLState:"+ae.getSQLState());
System.out.println("VendorError:"+ae.getErrorCode());
JOptionPane.showMessageDialog(p8,"Error in submitting data!");
}
JList li1=new JList(dl1);
JList li2=new JList(dl2);
JList li3=new JList(dl3);
JList li9=new JList(dl9);
li1.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
li1.setVisibleRowCount(2);
li2.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
li2.setVisibleRowCount(2);
li3.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
li3.setVisibleRowCount(2);
li9.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
li9.setVisibleRowCount(2);
f8.add(p8);
g8.gridx=0;
g8.gridy=0;
p8.add(l40,g8);
g8.gridx=1;
g8.gridy=0;
p8.add(t38,g8);
g8.gridx=0;
g8.gridy=1;
p8.add(l41,g8);
g8.gridx=1;
g8.gridy=1;
p8.add(new JScrollPane(li3),g8);
g8.gridx=0;
g8.gridy=2;
p8.add(l42,g8);
g8.gridx=1;
g8.gridy=2;
p8.add(new JScrollPane(li2),g8);
g8.gridx=0;
g8.gridy=3;
p8.add(l43,g8);
g8.gridx=1;
g8.gridy=3;
p8.add(new JScrollPane(li1),g8);
g8.gridx=0;
g8.gridy=4;
p8.add(l56,g8);
g8.gridx=1;
g8.gridy=4;
p8.add(new JScrollPane(li9),g8);
g8.gridx=0;
g8.gridy=5;
p8.add(l44,g8);
g8.gridx=1;
g8.gridy=5;
p8.add(t39,g8);
g8.gridx=2;
g8.gridy=5;
p8.add(l45,g8);
g8.gridx=0;
g8.gridy=6;
p8.add(b21,g8);
g8.gridx=1;
g8.gridy=6;
p8.add(b22,g8);
int a1=li1.getSelectedIndex();
int a2=li2.getSelectedIndex();
int a3=li3.getSelectedIndex();
int a10=li9.getSelectedIndex();
final String st1=(String) dl1.elementAt(a1);
final String st2=(String) dl2.elementAt(a2);
final String st3=(String) dl3.elementAt(a3);
final String st10=(String)dl9.elementAt(a10);