Java JTextField提示空指针异常


public class manageBikePanel extends JPanel {    private JTextField bikeIDF;
    private JTextField bikeNameF;
    private JTextField bikeTypeF;
    private JTextField bikeBrandF;
    private JTextField bikeSupplierF;
    //private JTextField supplierNameT;
    private JTextField importPriceF;
    private JTextField salePriceF;
    private JTextField importCycleF;
    //private JComboBox bikeTypeBox;
    private JComboBox bikeBox;
    //private JComboBox supplierBox;
    private JButton resetButton;    public manageBikePanel() {
        setLayout(new GridBagLayout());
        setBounds(10, 10, 510, 302);        setupComponet(new JLabel("选择自行车："), 0, 0, 1, 1, false);
        bikeBox = new JComboBox();
        bikeBox.setPreferredSize(new Dimension(1, 21));
        initComboBox();// 初始化下拉选择框
        // 处理供应商信息的下拉选择框的选择事件
        bikeBox.addActionListener(new ActionListener() {            public void actionPerformed(ActionEvent e) {
                doBikeSelectAction();
            }
        });
        setupComponet(bikeBox, 1, 0, 1, 160, true);        setupComponet(new JLabel("自行车名称："), 2, 0, 1, 1, false);
        bikeNameF = new JTextField();
        setupComponet(bikeNameF, 3, 0, 1, 160, true);        setupComponet(new JLabel("自行车型号："), 0, 1, 1, 1, false);
        bikeIDF = new JTextField();
        setupComponet(bikeIDF, 1, 1, 1, 0, true);        setupComponet(new JLabel("自行车类型："), 2, 1, 1, 1, false);
        bikeTypeF = new JTextField();
        //supplierPostT.addKeyListener(new InputKeyListener());
        setupComponet(bikeTypeF, 3, 1, 1, 0, true);        setupComponet(new JLabel("品牌："), 0, 2, 1, 1, false);
        bikeBrandF = new JTextField();
        //supplierTelT.addKeyListener(new InputKeyListener());
        setupComponet(bikeBrandF, 1, 2, 1, 0, true);        setupComponet(new JLabel("供应商："), 2, 2, 1, 1, false);
        bikeSupplierF = new JTextField();
        setupComponet(bikeSupplierF, 3, 2, 1, 0, true);        setupComponet(new JLabel("进价："), 0, 3, 1, 1, false);
        importPriceF = new JTextField();
        importPriceF.addKeyListener(new InputKeyListener());
        setupComponet(importPriceF, 1, 3, 1, 0, true);        setupComponet(new JLabel("售价："), 2, 3, 1, 1, false);
        salePriceF = new JTextField();
        salePriceF.addKeyListener(new InputKeyListener());
        setupComponet(salePriceF, 3, 3, 1, 0, true);        setupComponet(new JLabel("进货周期："), 0, 4, 1, 1, false);
        importCycleF = new JTextField();
        importCycleF.addKeyListener(new InputKeyListener());
        setupComponet(importCycleF, 1, 4, 1, 0, true);        JButton modifyButton = new JButton("修改");
        JButton delButton = new JButton("删除");
        JPanel panel = new JPanel();
        panel.add(modifyButton);
        panel.add(delButton);
        // 定位按钮
        setupComponet(panel, 3, 6, 1, 0, false);
        // 处理删除按钮的单击事件
        delButton.addActionListener(new DelActionListener());
        // 处理修改按钮的单击事件
        modifyButton.addActionListener(new ModifyActionListener());
    }
    // 初始化供应商下拉选择框    public void initComboBox() {
        List bikeInfo = dao.getBikeInfos();
        List<item> items = new ArrayList<item>();
        bikeBox.removeAllItems();
        for (Iterator iter = bikeInfo.iterator(); iter.hasNext();) {
            List element = (List) iter.next();
            item item = new item();
            item.setId(element.get(0).toString().trim());
            item.setName(element.get(1).toString().trim());
            if (items.contains(item)) {
                continue;
            }
            items.add(item);
            bikeBox.addItem(item);
        }
        doBikeSelectAction();
    }
    // 设置组件位置并添加到容器中    private void setupComponet(JComponent component, int gridx, int gridy,
            int gridwidth, int ipadx, boolean fill) {
        final GridBagConstraints gridBagConstrains = new GridBagConstraints();
        gridBagConstrains.gridx = gridx;
        gridBagConstrains.gridy = gridy;
        if (gridwidth > 1) {
            gridBagConstrains.gridwidth = gridwidth;
        }
        if (ipadx > 0) {
            gridBagConstrains.ipadx = ipadx;
        }
        gridBagConstrains.insets = new Insets(5, 1, 3, 1);
        if (fill) {
            gridBagConstrains.fill = GridBagConstraints.HORIZONTAL;
        }
        add(component, gridBagConstrains);
    }
    // 处理供应商选择事件    private void doBikeSelectAction() {
        item selectedItem;
        if (!(bikeBox.getSelectedItem() instanceof item)) {
            return;
        }
        selectedItem = (item) bikeBox.getSelectedItem();
        bikeInfo info = dao.getBikeInfo(selectedItem);
            if (!info.getBikeID().isEmpty()) {
            bikeIDF.setText(info.getBikeID());0000]从这里提示空指针异常[/color]
            bikeNameF.setText(info.getBikeName());
            bikeTypeF.setText(info.getBikeType());
            bikeBrandF.setText(info.getBikeBrand());
            bikeSupplierF.setText(info.getBikeSupplier());
            importPriceF.setText(String.valueOf(info.getImportPrice()));
            salePriceF.setText(String.valueOf(info.getSalePrice()));
            importCycleF.setText(String.valueOf(info.getImportCycle()));
        }
    }
}错误提示
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at internalFrame.mangeBike.manageBikePanel.doBikeSelectAction(manageBikePanel.java:164)
at internalFrame.mangeBike.manageBikePanel.initComboBox(manageBikePanel.java:131)
at internalFrame.mangeBike.manageBikePanel.<init>(manageBikePanel.java:55)
at internalFrame.manageBike.<init>(manageBike.java:29)
at com.mainFram.systemFrame1.jButton2ActionPerformed(systemFrame1.java:146)
at com.mainFram.systemFrame1.access$100(systemFrame1.java:20)
at com.mainFram.systemFrame1$2.actionPerformed(systemFrame1.java:59)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
at java.awt.Component.processMouseEvent(Component.java:6288)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
at java.awt.Component.processEvent(Component.java:6053)
at java.awt.Container.processEvent(Container.java:2041)
at java.awt.Component.dispatchEventImpl(Component.java:4651)
at java.awt.Container.dispatchEventImpl(Container.java:2099)
at java.awt.Component.dispatchEvent(Component.java:4481)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4577)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4238)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168)
at java.awt.Container.dispatchEventImpl(Container.java:2085)
at java.awt.Window.dispatchEventImpl(Window.java:2478)
at java.awt.Component.dispatchEvent(Component.java:4481)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:643)
at java.awt.EventQueue.access$000(EventQueue.java:84)
at java.awt.EventQueue$1.run(EventQueue.java:602)
at java.awt.EventQueue$1.run(EventQueue.java:600)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98)
at java.awt.EventQueue$2.run(EventQueue.java:616)
at java.awt.EventQueue$2.run(EventQueue.java:614)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:613)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)