java - 将行添加到数据模型时出现 ArrayIndexOutOfBoundsException

Question

我很抱歉提出了一个已经以各种形式被多次提出的问题，但我尚未找到有效的完整答案。我想做的就是将一行追加到表模型中。我尝试过用很多不同的方式来做这件事，但总是遇到类似的问题(或者有时是新的和令人兴奋的问题)。无论如何，当我尝试添加行时，我收到“ArrayIndexOutOfBoundsException”错误。我在下面的代码中标记了发生错误的行。我还包含了我看到的错误和我一直在使用的调试输出。我知道我实际上并不需要为您在此处看到的内容扩展 DefaultTableModel，但这是一个精简版本，我一直在使用它来追踪错误。

异常(exception):

Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: 2 > 0 at java.util.Vector.insertElementAt(Vector.java:594) at javax.swing.table.DefaultTableModel.insertRow(DefaultTableModel.java:374) at javax.swing.table.DefaultTableModel.addRow(DefaultTableModel.java:350) at javax.swing.table.DefaultTableModel.addRow(DefaultTableModel.java:361) at SMC.RoleCard$1.actionPerformed(RoleCard.java:69) at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018) at javax.swing.AbstractButton$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:729) at java.awt.EventQueue.access$200(EventQueue.java:103) at java.awt.EventQueue$3.run(EventQueue.java:688) at java.awt.EventQueue$3.run(EventQueue.java:686) 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:702) at java.awt.EventQueue$4.run(EventQueue.java:700) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76) at java.awt.EventQueue.dispatchEvent(EventQueue.java:699) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138) at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)

调试输出:

There are 2 elements in roleData
roleData has 2 elements
Performing WHILE loop
tableData[0][0] is assigned ECC
tableData[0][1] is assigned 1
Performing WHILE loop
tableData[1][0] is assigned Portal
tableData[1][1] is assigned 2
Called getColumnCount()
Returned 2
tableDate has 2 columns and 2 rows.
Called getColumnCount()
Returned 2
Called getColumnName()
Returned Role
Called getColumnCount()
Returned 2
Called getColumnName()
Returned Sort Order
Called getColumnCount()
Returned 2
arg is :Role Data:
Clicked on Role
Called getColumnClass()
Called getColumnClass()
Called getColumnClass()
Called getColumnClass()
B: There are 2 rows in RoleTableModel
Add was pressed

代码:

package SMC;

import java.awt.Component;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.Vector;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;

/**
 * @author Larry Krigbaum
 */
public class RoleCard
{
    public JPanel getRoleCard()
    {
        final JPanel roleCard = new JPanel();
        roleCard.setLayout(new BoxLayout(roleCard, BoxLayout.PAGE_AXIS));
        roleCard.setAlignmentX(Component.CENTER_ALIGNMENT);
        JPanel role_title = new JPanel();
        role_title.add(new JLabel(" "));
        role_title.add(new JLabel("Configure SAP Roles"));
        role_title.add(new JLabel(" "));
        roleCard.add(role_title);

        final JPanel role_table = new JPanel();
        String[] roleColumnNames = {"Role", "Sort Order"};
        ArrayList<Role> roleData = Role.loadRoleData();
        System.out.println("There are " + roleData.size() + " elements in roleData");
        //ArrayList<Role> roleData = null;
        final RoleTableModel roleTableModel = new RoleTableModel(roleColumnNames, roleData);
        JTable roleEditTable = new JTable(roleTableModel);
        roleEditTable.setAutoCreateRowSorter(true);
        //final DefaultTableModel roleTableModel = (DefaultTableModel) roleEditTable.getModel();
        //final JTable roleEditTable = getRoleTable();
        role_table.add(new JScrollPane(roleEditTable));                         // ScrollPane needed to show headers
        roleCard.add(role_table);

        JPanel buttonPanel = new JPanel();
        JButton addButton = new JButton("Add");
        addButton.setActionCommand("Add");
        JButton deleteButton = new JButton("Delete");
        deleteButton.setActionCommand("Delete");
        final JButton cancelButton = new JButton("Cancel");
        cancelButton.setActionCommand("Cancel");
        cancelButton.setEnabled(false);
        buttonPanel.add(addButton);
        buttonPanel.add(deleteButton);
        buttonPanel.add(cancelButton);
        roleCard.add(buttonPanel);
        addButton.addActionListener(new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                System.out.println("B: There are " + roleTableModel.getRowCount() + " rows in RoleTableModel");
                System.out.println("Add was pressed");
                cancelButton.setEnabled(true);
                Object[] newRole = null;
                roleTableModel.addRow(newRole);
                //Object[] newRole = new Object[] {" ", " "};
                System.out.println("A: There are " + roleTableModel.getRowCount() + " rows in RoleTableModel");
                //roleTableModel.setRowCount((roleTableModel.getRowCount()) + 1);
                System.out.println("B: There are " + roleTableModel.getRowCount() + " rows in RoleTableModel");
                roleTableModel.fireTableRowsInserted(roleTableModel.getRowCount(), roleTableModel.getRowCount());
                roleTableModel.fireTableDataChanged();
            }
        });
        deleteButton.addActionListener(new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                System.out.println("Delete was pressed");
                cancelButton.setEnabled(true);
            }
        });
        cancelButton.addActionListener(new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                System.out.println("Cancel was pressed");
                cancelButton.setEnabled(false);
            }
        });

        return roleCard;
    }

class RoleTableModel extends DefaultTableModel
{
    private String[] roleColumnNames = {"Role", "Sort Order"};
    private Object[][] tableData;

    public RoleTableModel(String[] roleColumnNames, ArrayList<Role> roleData)
    {
        System.out.println("roleData has " + roleData.size() + " elements");
        tableData = new Object[roleData.size()][2];
        Role role = new Role();

        Collections.sort(roleData, Role.MakeComparator);
        Iterator rolesOrderByRole = roleData.iterator();
        int i = 0;
        while (rolesOrderByRole.hasNext())
        {
            System.out.println("Performing WHILE loop");
            role = (Role)rolesOrderByRole.next();
            tableData[i][0] = role.xrole;
            System.out.println("tableData[" + i + "][0] is assigned " + tableData[i][0]);
            tableData[i][1] = role.sortOrder;
            System.out.println("tableData[" + i + "][1] is assigned " + tableData[i][1]);
            i++;
        }
        System.out.println("tableDate has " + getColumnCount() + " columns and " + getRowCount() + " rows.");
    }

   @Override
    public int getColumnCount() 
    {
        System.out.println("Called getColumnCount()");
        System.out.println("Returned " + roleColumnNames.length);
        return roleColumnNames.length;
    }

    @Override
    public int getRowCount()
    {
       if (tableData == null)
           return 0;
       return tableData.length;
    }

    @Override
    public String getColumnName(int col) 
    {
        System.out.println("Called getColumnName()");
        System.out.println("Returned " + roleColumnNames[col]);
        return roleColumnNames[col];
    }

    @Override
    public Object getValueAt(int row, int col) 
    {
        return tableData[row][col];
    }

    @Override
    public Class getColumnClass(int c) 
    {
        System.out.println("Called getColumnClass()");
        return getValueAt(0, c).getClass();
    }

    /*
     * Don't need to implement this method unless your table's
     * editable.
     */
    @Override
    public boolean isCellEditable(int row, int col) 
    {
        System.out.println("Called isCellEditable()");
        //Note that the data/cell address is constant,
        //no matter where the cell appears onscreen.
        return true;
    }

    /*
     * Don't need to implement this method unless your table's
     * data can change.
     */
    @Override
    public void setValueAt(Object value, int row, int col)
    {
        System.out.println("Called setValueAt()");
        tableData[row][col] = value;
        fireTableCellUpdated(row, col);
    }
}

Answer 1

您正在通过扩展 DefaultTableModel 创建表模型。但是，您不是委托(delegate)其方法来存储数据，而是将它们存储在单独的数据数组中。并且您重写了一些方法而不是其他方法。结果是，有时，使用父类(super class)的方法，尝试在父类(super class)持有的 vector 中获取和插入数据，有时，使用子类方法，从子类数组获取和设置值数据。

如果您需要定义自定义 TableModel 实现，请扩展 AsbtractTableModel 并根据需要定义所有内容，或者扩展 DefaultTableModel 但不添加定义任何字段。只重写需要重写的方法，并委托(delegate)给父类(super class)方法。

除了 getColumnClass() 之外，我没有看到任何理由重写 DefaultTableModel 中的任何方法。