isCellEditable和数据库不能一起工作

Question

更改单元格值后，我的JTable不会刷新。我可以双击一个单元格并更改它的值，但是当我按OK或者我点击离开单元格时，值会重置为上一个，这不是更新表。这是我的自定义表模型的代码，我不知道如何更新数据库，因为当我改变单元格的值时，表是从一个db中取出来的。

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;
    }


}

如果您需要其他东西，例如数据库或表编辑器的代码，请告诉我；）谢谢您的帮助：）

--编辑--好的，我已经实现了setValueAt方法，但是当我单击单元格时，它给出了如下错误

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);
    }

请你再帮我一次好吗？：）我对这个函数非常着迷，我知道对很多人来说没什么难的，但对我来说却是...谢谢你的回答，祝你有个愉快的一天！：d

更新：我已使用以下代码解决了此问题：[CODE]@override 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，然后刷新它的视图，这样它几乎可以显示新的值。谢谢大家给我的帮助和启发，我们终于成功了！！*_*

Answer 1

我在您的TableModel中看不到setValueat()的任何实现。没有它，你怎么能指望这两件事发生呢？尝试实现那个方法，看看你是否做得更好。

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，并检查对象引用。在调试器中运行以查看哪个为空。会很容易修好的。

看到这一行了吗？

Vector<Paziente> content;

它将引用设置为null，因为您没有调用new将其设置为新引用。

将其改为这个,NPE就会消失：

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

这可能不是您想要的，但它不会是空的。

我认为您应该处理的是底层表模型，而不是这个随机向量。你知道你的代码，但我认为这也不会让你高兴。

我强烈建议您在尝试真正的问题之前,先简化程序,学习一下JTable教程：

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