Question

更改单元格值后，我的JTable未刷新。我可以双击单元格并更改它的值，但是当我按下OK或单击单元格时，值将重置为上一个，它不会更新表格。这是我的自定义表模型的代码，我不知道如何更新数据库，因为当我更改单元格的值时，表是从数据库中获取的。

package adisys.server.strumenti;

import java.sql.*;
import java.util.Formatter;

import javax.swing.event.TableModelEvent;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.TableModel;

import adisys.server.boundary.EditorPatologie;
import adisys.server.data.Database;
import adisys.server.data.Patologie;
import adisys.server.entity.Patologia;


/**
 * @author Francesco
 *
 */
public class ADISysTableModel extends AbstractTableModel implements TableModel {


    ResultSet dati;

    public ADISysTableModel(ResultSet nuoviDati)
    {
        dati=nuoviDati;

        try {
            //Trace
            System.out.println("- Creazione modello tabella: \""+ dati.getMetaData().getTableName(1) +"\"");
        } catch (SQLException e1) {
            e1.printStackTrace();
        }

    }

    @Override
    public int getColumnCount() {

        try {
            return dati.getMetaData().getColumnCount();
        } 
        catch (SQLException e) {
            e.printStackTrace();
            System.out.println("ERRORE: Calcolo del numero di colonne errato.");
            return 0;
        }
    }

    @Override
    public int getRowCount() {

        try {
            //Seleziona l'ultimo elemento
            dati.last();
            //Restituisce l'indice dell'elemento
            return (dati.getRow());


        } catch (SQLException e) {
            e.printStackTrace();
            System.out.println("ERRORE: Calcolo del numero di righe errato. (metodo getRowCount() )");
            return 0;
        }
    }

    @Override
    public Object getValueAt(int riga, int colonna) {

        try {
            //Sposta il cursore alla riga desiderata (con sfasamento di 1)
            dati.absolute(riga+1);

            //Estrae il valore nella colonna specificata e lo restituisce (con sfasamento di 1)
            return dati.getObject(colonna+1);

        } catch (SQLException e) {
            // In caso di errore restituisce un oggetto vuoto
            e.printStackTrace();

            //Trace
            System.out.println("ERRORE: Valore dell'elemento della tabella non valido.");
            return null;
        }
    }

    @Override
    public boolean isCellEditable(int rIndex, int cIndex)
    {
        return true;
    }


    @Override
    public String getColumnName(int col) {
        try {
            return dati.getMetaData().getColumnName(col+1);
        } catch (SQLException e) {
            // Eccezione
            e.printStackTrace();
            return "?";
        }
    }

    public Integer getID(int riga)
    {
        //Ricerca colonna ID
        for(int i=0; i<=getColumnCount(); i++)
            if(getColumnName(i).equals("ID"))
                return i;
        return null;
    }


    /**
     * Restituisce l'indice della colonna a partire dal nome della colonna ricercata
     * <b>N.B. L'indice della prima colonna è 0, l'ultimo è numeroColonne-1.</b>
     * @param Nome - Stringa con il nome della colonna
     * @return -1 se la colonna non e' stata trovata, altrimenti l'indice della colonna
     */
    public int getColumnIndex(String Nome)
    {
        for (int i=0; i<getColumnCount();i++)
            if( getColumnName(i)==Nome) return i;
        return -1;
    }


}

如果您需要其他内容，例如数据库代码或表格编辑器，请告诉我们;）感谢您的帮助：）

- EDIT-- 好吧我已经实现了setValueAt方法但是当我点击单元格时它会给我这样的错误

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at adisys.server.strumenti.ADISysTableModel.setValueAt(ADISysTableModel.java:149)
    at javax.swing.JTable.setValueAt(Unknown Source)
    at javax.swing.JTable.editingStopped(Unknown Source)
    at javax.swing.AbstractCellEditor.fireEditingStopped(Unknown Source)
    at javax.swing.DefaultCellEditor$EditorDelegate.stopCellEditing(Unknown Source)
    at javax.swing.DefaultCellEditor.stopCellEditing(Unknown Source)
    at javax.swing.JTable$GenericEditor.stopCellEditing(Unknown Source)
    at javax.swing.DefaultCellEditor$EditorDelegate.actionPerformed(Unknown Source)
    at javax.swing.JTextField.fireActionPerformed(Unknown Source)
    at javax.swing.JTextField.postActionEvent(Unknown Source)
    at javax.swing.JTextField$NotifyAction.actionPerformed(Unknown Source)
    at javax.swing.SwingUtilities.notifyAction(Unknown Source)
    at javax.swing.JComponent.processKeyBinding(Unknown Source)
    at javax.swing.JComponent.processKeyBindings(Unknown Source)
    at javax.swing.JComponent.processKeyEvent(Unknown Source)
    at java.awt.Component.processEvent(Unknown Source)
    at java.awt.Container.processEvent(Unknown Source)
    at java.awt.Component.dispatchEventImpl(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.KeyboardFocusManager.redispatchEvent(Unknown Source)
    at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(Unknown Source)
    at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(Unknown Source)
    at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(Unknown Source)
    at java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source)
    at java.awt.Component.dispatchEventImpl(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Window.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access$200(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)

我的setValueAt方法是这样的：

Vector<Paziente> content;

    @Override
    public void setValueAt(Object value, int rowIndex, int columnIndex)
    {
        Paziente row = this.content.elementAt(rowIndex);
        String strValue = (String)value;
        int IDValue = (int)value;
        if(columnIndex == 0)
        {
            row.setID(IDValue);
        }
        else if(columnIndex == 1)
        {
            row.setNome(strValue);
        }
        else if(columnIndex == 2)
        {
            row.setCognome(strValue);
        }
        fireTableCellUpdated(rowIndex, columnIndex);
    }

请你再帮我一次吗？ :)我对这个功能感到疯狂，我知道对于很多人来说并不困难，但对我来说这是......感谢您的答案，祝您有愉快的一天！：d

更新：我用这段代码解决了这个问题： [码] @覆盖 public void setValueAt（Object value，int rowIndex，int columnIndex） {String aValue =（String）value; String formatoIstruzione =“UPDATE PAZIENTI SET NOME =”+“'”+ aValue +“'”+“WHERE ID =”+ rowIndex +“;”; Database.esegui（formatoIstruzione.toUpperCase（））; Pianificatore.aggiornaTabelle（）; } } [/ CODE]

换句话说，我启动sql指令来更新表，然后我刷新它的视图，所以它几乎显示新的值。谢谢大家的帮助和你给我的灵感，我们终于得到了它！ *的 _ *

Answer 1

我在setValueAt()中看不到TableModel的任何实施。如果没有它，你怎么能指望这些事情发生？尝试实施该方法，看看你做得更好。

更新：

ADISysTableModel中的第149行有一个空引用：

at adisys.server.strumenti.ADISysTableModel.setValueAt(ADISysTableModel.java:149)

打开文本编辑器，转到该行号，然后检查对象引用。在调试器中运行以查看哪个为null。它很容易修复。

看到这一行？

Vector<Paziente> content;

将引用设置为null，因为您没有调用new来将其设置为新引用。

将其更改为此并且NPE消失：

Vector<Paziente> content = new Vector<Paziente>();

这可能不是您想要的，但它不会为空。

我认为你应该处理基础表模型，而不是这个随机向量。你知道你的代码，但我认为这不会让你开心。

我强烈建议您在尝试解决实际问题之前先简化一些事情并阅读JTable教程：

http://docs.oracle.com/javase/tutorial/uiswing/components/table.html

isCellEditable和数据库不能一起工作

1 个答案: