在JTable中使用setAutoCreateRowSorter对不同的数据类型进行排序

本文介绍了在JTable中使用setAutoCreateRowSorter对不同的数据类型进行排序的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我正在通过Java查询MySQL数据库，将数据从结果集中提取出来并将其放入DefaultTableModel中，该模型将放入JTable中，然后放入JScrollPane中以进行显示.

I am querying a MySQL database via Java, pulling data out of the result set and placing it in a DefaultTableModel, which gets put in a JTable, then into a JScrollPane to get displayed.

在JTable中，我可以通过

In the JTable, I enable sorting in the table via

table.setAutoCreateRowSorter(true);

但是，如果我要排序的行中的单元格不是String类，则将收到java.lang.ClassCastException.我表中的数据具有以下类别:

However, if the cells in the row I want to sort are not of class String, then I get a java.lang.ClassCastException. The data in my table has the following classes:

java.sql.Date java.sql.Time java.lang.Double java.lang.Boolean java.lang.String

以下是当我尝试对类java.lang.Double的列进行排序时遇到的错误，随后是将结果集作为输入输出的类，它输出JTable.如果有人对如何解决排序问题有任何想法，将不胜感激.

Below is the error I get when I try to sort a column of class java.lang.Double, followed by the class that takes the result set as input out outputs the JTable. If anyone has any ideas on how I can fix my sorting problem it would be greatly appreciated.

Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: java.lang.Double `enter code here`cannot be cast to java.lang.String at java.text.Collatorpare(Collator.java:327) at javax.swing.DefaultRowSorterpare(DefaultRowSorter.java:968) at javax.swing.DefaultRowSorter.access$100(DefaultRowSorter.java:112) at javax.swing.DefaultRowSorter$RowpareTo(DefaultRowSorter.java:1376) at javax.swing.DefaultRowSorter$RowpareTo(DefaultRowSorter.java:1366) at java.util.ComparableTimSort.countRunAndMakeAscending(ComparableTimSort.java:290) at java.util.ComparableTimSort.sort(ComparableTimSort.java:157) at java.util.ComparableTimSort.sort(ComparableTimSort.java:146) at java.util.Arrays.sort(Arrays.java:472) at javax.swing.DefaultRowSorter.sort(DefaultRowSorter.java:607) at javax.swing.DefaultRowSorter.setSortKeys(DefaultRowSorter.java:319) at javax.swing.DefaultRowSorter.toggleSortOrder(DefaultRowSorter.java:480) at javax.swing.plaf.basic.BasicTableHeaderUI$MouseInputHandler.mouseClicked(BasicTableHeaderUI.java:112) at java.awt.AWTEventMulticaster.mouseClicked(AWTEventMulticaster.java:270) at java.awt.AWTEventMulticaster.mouseClicked(AWTEventMulticaster.java:269) at java.awt.Component.processMouseEvent(Component.java:6508) 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:4501) at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422) at java.awt.Container.dispatchEventImpl(Container.java:2273) at java.awt.Window.dispatchEventImpl(Window.java:2713) at java.awt.Component.dispatchEvent(Component.java:4687) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707) at java.awt.EventQueue.access$000(EventQueue.java:101) at java.awt.EventQueue$3.run(EventQueue.java:666) at java.awt.EventQueue$3.run(EventQueue.java:664) 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:680) at java.awt.EventQueue$4.run(EventQueue.java:678) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76) at java.awt.EventQueue.dispatchEvent(EventQueue.java:677) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105) at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)

以下是该课程的来源:

import java.awt.Component; import java.awt.Dimension; import java.awt.event.ItemEvent; import java.awt.event.ItemListener; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.SQLException; import java.util.Vector; import java.util.logging.Level; import java.util.logging.Logger; import javax.swing.JFrame; import javax.swing.JTable; import javax.swing.JToggleButton; import javax.swing.UIManager; import javax.swing.event.TableModelEvent; import javax.swing.event.TableModelListener; import javax.swing.table.*; public class ResultSetToCheckBoxTable { private int numberOfColumns; private DefaultTableModel model; private ResultSetMetaData metaData; private JTable table; private ResultSet rs; private TableColumn tc; public JTable getTable() { return table; } public ResultSetToCheckBoxTable(ResultSet rs) { try { this.rs = rs; //overrides getColumnClass method in DefaultTableModel to help make checkbox model = new DefaultTableModel() { @Override public Class<?> getColumnClass(int columnIndex) { if (columnIndex == numberOfColumns) { return Boolean.class; } else { //return getValueAt(0, columnIndex).getClass(); return String.class; } } }; // Get the column names metaData = this.rs.getMetaData(); numberOfColumns = metaData.getColumnCount(); for (int column = 1; column <= numberOfColumns; column++) { model.addColumn(metaData.getColumnLabel(column)); } model.addColumn(""); // Get the table info while (rs.next()) { Vector tableRow = new Vector(); for (int i = 1; i <= numberOfColumns; i++) { tableRow.addElement(rs.getObject(i)); } tableRow.addElement(true); model.addRow(tableRow); } //Create JTable using the model & set options table = new JTable(model) { @Override public boolean isCellEditable(int row, int column) { return false; }; }; table.setAutoCreateRowSorter(true); table.setPreferredScrollableViewportSize(new Dimension(320, 160)); //Rest of the stuff tc = table.getColumnModel().getColumn(numberOfColumns); tc.setHeaderRenderer(new SelectAllHeader(table, numberOfColumns)); } catch (SQLException ex) { Logger.getLogger(ResultSetToCheckBoxTable.class.getName()).log(Level.SEVERE, null, ex); } } public static void main(String[] args) { } } /** * A TableCellRenderer that selects all or none of a Boolean column. * * @param numberOfColumns the Boolean column to manage */ class SelectAllHeader extends JToggleButton implements TableCellRenderer { private static final String ALL = "✓ Select all"; private static final String NONE = "✓ Select none"; private JTable table; private TableModel tableModel; private JTableHeader header; private TableColumnModel tcm; private int targetColumn; private int viewColumn; public SelectAllHeader(JTable table, int targetColumn) { super(ALL); this.table = table; this.tableModel = table.getModel(); if (tableModel.getColumnClass(targetColumn) != Boolean.class) { throw new IllegalArgumentException("Boolean column required."); } this.targetColumn = targetColumn; this.header = table.getTableHeader(); this.tcm = table.getColumnModel(); this.applyUI(); this.addItemListener(new ItemHandler()); header.addMouseListener(new MouseHandler()); tableModel.addTableModelListener(new ModelHandler()); } @Override public Component getTableCellRendererComponent( JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) { return this; } private class ItemHandler implements ItemListener { @Override public void itemStateChanged(ItemEvent e) { boolean state = e.getStateChange() == ItemEvent.SELECTED; setText((state) ? NONE : ALL); for (int r = 0; r < table.getRowCount(); r++) { table.setValueAt(state, r, viewColumn); } } } @Override public void updateUI() { super.updateUI(); applyUI(); } private void applyUI() { this.setFont(UIManager.getFont("TableHeader.font")); this.setBorder(UIManager.getBorder("TableHeader.cellBorder")); this.setBackground(UIManager.getColor("TableHeader.background")); this.setForeground(UIManager.getColor("TableHeader.foreground")); } private class MouseHandler extends MouseAdapter { @Override public void mouseClicked(MouseEvent e) { viewColumn = header.columnAtPoint(e.getPoint()); int modelColumn = tcm.getColumn(viewColumn).getModelIndex(); if (modelColumn == targetColumn) { doClick(); } } } private class ModelHandler implements TableModelListener { @Override public void tableChanged(TableModelEvent e) { if (needsToggle()) { doClick(); header.repaint(); } } } // Return true if this toggle needs to match the model. private boolean needsToggle() { boolean allTrue = true; boolean allFalse = true; for (int r = 0; r < tableModel.getRowCount(); r++) { boolean b = (Boolean) tableModel.getValueAt(r, targetColumn); allTrue &= b; allFalse &= !b; } return allTrue && !isSelected() || allFalse && isSelected(); } }

推荐答案

问题是，您告诉JTable您所有的列都包含Strings(包括最后一个字符串)，这是不正确的:

The problem is that you told the JTable that all your columns contain Strings (escpt the last one), which is not true:

public Class<?> getColumnClass(int columnIndex) { if (columnIndex == numberOfColumns) { return Boolean.class; } else { //return getValueAt(0, columnIndex).getClass(); return String.class; } }

将事实告诉JTable，它将很高兴.

Tell the truth to the JTable, and it will be happy.