当所选项目不为空时，JComboBox 似乎返回空值

Question

这是我的问题。我创建了一个 JForm，它应该有助于在数据库中插入新对象“Analyse”，而这些“Analyse”对象需要创建“Lot”对象 ID。

所以我创建了一个 JCombobox，它允许我选择一个“Lot”id。组合框渲染器允许我查看该值，该值不为空，但我使用提交按钮时返回的值为空...

这是错误代码：

Internal Exception: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Column 'id_lot' cannot be null
Error Code: 1048
Call: INSERT INTO analyses (date_validite, id_lot) VALUES (?, ?)
        bind => [2015-03-10, null]
Query: InsertObjectQuery(analysesmanager.Analyses[idAnalyse=null])

我知道为什么会出现该错误...我不知道不允许用户使用空 id_lot 添加分析。这是正常的。异常部分是我的 JForm 发送空值...

这是 JForm 代码：

package analysesmanager;

import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;

/**
 *
 * @author m.desmidt
 */
public class NewAnalyse extends javax.swing.JDialog {

    protected Analyses currentRecord;

    /**
     * Get the value of currentRecord
     *
     * @return the value of currentRecord
     */
    public Analyses getCurrentRecord() {
        return currentRecord;
    }

    /**
     * Set the value of currentRecord
     *
     * @param currentRecord new value of currentRecord
     */
    public void setCurrentRecord(Analyses currentRecord) {
        Analyses oldRecord = this.currentRecord;
        this.currentRecord = currentRecord;
        propertyChangeSupport.firePropertyChange("currentRecord", oldRecord, currentRecord);

    }
    private PropertyChangeSupport propertyChangeSupport = new PropertyChangeSupport(this);
    protected boolean AnalyseConfirmed;

    /**
     * Get the value of AnalyseConfirmed
     *
     * @return the value of AnalyseConfirmed
     */
    public boolean isAnalyseConfirmed() {
        return AnalyseConfirmed;
    }

    /**
     * Set the value of AnalyseConfirmed
     *
     * @param AnalyseConfirmed new value of AnalyseConfirmed
     */
    public void setAnalyseConfirmed(boolean AnalyseConfirmed) {
        this.AnalyseConfirmed = AnalyseConfirmed;
    }

    /**
     * Add PropertyChangeListener.
     *
     * @param listener
     */
    @Override
    public void addPropertyChangeListener(PropertyChangeListener listener) {
        propertyChangeSupport.addPropertyChangeListener(listener);
    }

    /**
     * Remove PropertyChangeListener.
     *
     * @param listener
     */
    @Override
    public void removePropertyChangeListener(PropertyChangeListener listener) {
        propertyChangeSupport.removePropertyChangeListener(listener);
    }

    /** Creates new form NewAnalyse */
    public NewAnalyse(java.awt.Frame parent, boolean modal) {
        super(parent, modal);
        initComponents();
    }

    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {
        bindingGroup = new org.jdesktop.beansbinding.BindingGroup();

        analyses_2PUEntityManager = java.beans.Beans.isDesignTime() ? null : javax.persistence.Persistence.createEntityManagerFactory("analyses_2PU").createEntityManager();
        lotsQuery = java.beans.Beans.isDesignTime() ? null : analyses_2PUEntityManager.createQuery("SELECT l FROM Lots l");
        lotsList = java.beans.Beans.isDesignTime() ? java.util.Collections.emptyList() : lotsQuery.getResultList();
        dateVerifier1 = new analysesmanager.DateVerifier();
        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jComboBox1 = new javax.swing.JComboBox();
        jButton1 = new javax.swing.JButton();
        jButton2 = new javax.swing.JButton();
        jLabel3 = new javax.swing.JLabel();
        jTextField2 = new javax.swing.JTextField();
        jFormattedTextField1 = new javax.swing.JFormattedTextField();
        lotsRenderer1 = new analysesmanager.LotsRenderer();

        setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);
        org.jdesktop.application.ResourceMap resourceMap = org.jdesktop.application.Application.getInstance(analysesmanager.AnalysesManagerApp.class).getContext().getResourceMap(NewAnalyse.class);
        setTitle(resourceMap.getString("Form.title")); // NOI18N
        setModal(true);
        setName("Form"); // NOI18N

        jLabel1.setText(resourceMap.getString("jLabel1.text")); // NOI18N
        jLabel1.setName("jLabel1"); // NOI18N

        jLabel2.setText(resourceMap.getString("jLabel2.text")); // NOI18N
        jLabel2.setName("jLabel2"); // NOI18N

        jComboBox1.setName("jComboBox1"); // NOI18N
        jComboBox1.setRenderer(lotsRenderer1);

        org.jdesktop.swingbinding.JComboBoxBinding jComboBoxBinding = org.jdesktop.swingbinding.SwingBindings.createJComboBoxBinding(org.jdesktop.beansbinding.AutoBinding.UpdateStrategy.READ_WRITE, lotsList, jComboBox1);
        bindingGroup.addBinding(jComboBoxBinding);
        org.jdesktop.beansbinding.Binding binding = org.jdesktop.beansbinding.Bindings.createAutoBinding(org.jdesktop.beansbinding.AutoBinding.UpdateStrategy.READ_WRITE, this, org.jdesktop.beansbinding.ELProperty.create("${currentRecord.lots.idLot}"), jComboBox1, org.jdesktop.beansbinding.BeanProperty.create("selectedItem"));
        bindingGroup.addBinding(binding);

        jButton1.setText(resourceMap.getString("jButton1.text")); // NOI18N
        jButton1.setName("jButton1"); // NOI18N
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                CancelAnalyse(evt);
            }
        });

        jButton2.setText(resourceMap.getString("jButton2.text")); // NOI18N
        jButton2.setName("jButton2"); // NOI18N
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                SaveAnalyse(evt);
            }
        });

        jLabel3.setText(resourceMap.getString("jLabel3.text")); // NOI18N
        jLabel3.setName("jLabel3"); // NOI18N

        jTextField2.setName("jTextField2"); // NOI18N

        binding = org.jdesktop.beansbinding.Bindings.createAutoBinding(org.jdesktop.beansbinding.AutoBinding.UpdateStrategy.READ_WRITE, this, org.jdesktop.beansbinding.ELProperty.create("${currentRecord.idAnalyse}"), jTextField2, org.jdesktop.beansbinding.BeanProperty.create("text"));
        bindingGroup.addBinding(binding);

        jFormattedTextField1.setFormatterFactory(new javax.swing.text.DefaultFormatterFactory(new javax.swing.text.DateFormatter()));
        jFormattedTextField1.setInputVerifier(dateVerifier1);
        jFormattedTextField1.setName("jFormattedTextField1"); // NOI18N

        binding = org.jdesktop.beansbinding.Bindings.createAutoBinding(org.jdesktop.beansbinding.AutoBinding.UpdateStrategy.READ_WRITE, this, org.jdesktop.beansbinding.ELProperty.create("${currentRecord.dateValidite}"), jFormattedTextField1, org.jdesktop.beansbinding.BeanProperty.create("value"));
        bindingGroup.addBinding(binding);

        lotsRenderer1.setText(resourceMap.getString("lotsRenderer1.text")); // NOI18N
        lotsRenderer1.setName("lotsRenderer1"); // NOI18N

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addComponent(jLabel1)
                            .addComponent(jLabel3)
                            .addComponent(jLabel2))
                        .addGap(26, 26, 26)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                            .addComponent(jFormattedTextField1, javax.swing.GroupLayout.DEFAULT_SIZE, 324, Short.MAX_VALUE)
                            .addComponent(jTextField2, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, 324, Short.MAX_VALUE)
                            .addComponent(jComboBox1, javax.swing.GroupLayout.Alignment.LEADING, 0, 324, Short.MAX_VALUE)))
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                        .addComponent(lotsRenderer1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 189, Short.MAX_VALUE)
                        .addComponent(jButton2)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(jButton1)))
                .addContainerGap())
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel1)
                    .addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jLabel3))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel2)
                    .addComponent(jFormattedTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jButton1)
                    .addComponent(jButton2)
                    .addComponent(lotsRenderer1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addContainerGap(22, Short.MAX_VALUE))
        );

        bindingGroup.bind();

        pack();
    }// </editor-fold>                        

    private void SaveAnalyse(java.awt.event.ActionEvent evt) {                             
        setAnalyseConfirmed(true);
        setVisible(false);
    }                            

    private void CancelAnalyse(java.awt.event.ActionEvent evt) {                               
        setAnalyseConfirmed(false);
        setVisible(false);
    }                              

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {
                NewAnalyse dialog = new NewAnalyse(new javax.swing.JFrame(), true);
                dialog.addWindowListener(new java.awt.event.WindowAdapter() {

                    @Override
                    public void windowClosing(java.awt.event.WindowEvent e) {
                        System.exit(0);
                    }
                });
                dialog.setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify                     
    private javax.persistence.EntityManager analyses_2PUEntityManager;
    private analysesmanager.DateVerifier dateVerifier1;
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JComboBox jComboBox1;
    private javax.swing.JFormattedTextField jFormattedTextField1;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JTextField jTextField2;
    private java.util.List<analysesmanager.Lots> lotsList;
    private javax.persistence.Query lotsQuery;
    private analysesmanager.LotsRenderer lotsRenderer1;
    private org.jdesktop.beansbinding.BindingGroup bindingGroup;
    // End of variables declaration                   
}

​​ 这是一个 屏幕 如何绑定我的 JCombobox。

我做错了什么？ 只要有用就可以接受火爆...

Answer 1

我设法使用一个小的解决方法......我没有选择“lots.idLot”，而是选择“lots”，然后找到它的“idlot”。

有用。这不是我一开始想要的方式，但它确实有效。