更新
已确认为 JTable can't format given Object as Number when columnClass is Double (bug ID: 7051636) 上的错误.请随意投票，或者如果您有替代(更好)的解决方法，请将其作为评论发布到报告中。
我正在构建一个 JTable，其中包含一个扩展 AbstractTableModel 的自定义表格模型。 我的模型需要支持空行才能显示和排序。 所以我跟着这个post实现它，现在工作得很好。
我仍然对 JTable 中的格式化字段有疑问。 假设我有以下模型:
public class MyModel extends AbstractTableModel{
public Object[] types= {new Integer(0), ""};
public static final Object EMPTY_ROW = "";
@Override
public Object getValueAt(int rowIndex, int columnIndex) {
return this.EMPTY_ROW;
}
public Class<? extends Object> getColumnClass(int c) {
if (c > this.types.length - 1)
return null;
else
return this.types[c].getClass();
}
}
一切正常。 但是如果我有一个 Double 而不是一个 Integer:
public class MyModel extends AbstractTableModel{
public Object[] types= {new Double(0.0), ""};
.......
我会得到一个非法参数异常:
编辑: @Aaron Digulla 建议后的新堆栈跟踪输出
Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: Cannot format given Object as a Number at java.text.DecimalFormat.format(DecimalFormat.java:487) at java.text.Format.format(Format.java:140) at javax.swing.JTable$DoubleRenderer.setValue(JTable.java:5352) at javax.swing.table.DefaultTableCellRenderer.getTableCellRendererComponent(DefaultTableCellRenderer.java:237) at javax.swing.JTable.prepareRenderer(JTable.java:5720) at javax.swing.plaf.basic.BasicTableUI.paintCell(BasicTableUI.java:2072) at javax.swing.plaf.basic.BasicTableUI.paintCells(BasicTableUI.java:1974) at javax.swing.plaf.basic.BasicTableUI.paint(BasicTableUI.java:1770) at javax.swing.plaf.ComponentUI.update(ComponentUI.java:143) at javax.swing.JComponent.paintComponent(JComponent.java:752) at javax.swing.JComponent.paint(JComponent.java:1029) at javax.swing.JComponent.paintChildren(JComponent.java:862) at javax.swing.JComponent.paint(JComponent.java:1038) at javax.swing.JViewport.paint(JViewport.java:747) at javax.swing.JComponent.paintChildren(JComponent.java:862) at javax.swing.JComponent.paint(JComponent.java:1038) at javax.swing.JComponent.paintChildren(JComponent.java:862) at javax.swing.JComponent.paint(JComponent.java:1038) at javax.swing.JComponent.paintChildren(JComponent.java:862) at javax.swing.JComponent.paint(JComponent.java:1038) at javax.swing.JLayeredPane.paint(JLayeredPane.java:567) at javax.swing.JComponent.paintChildren(JComponent.java:862) at javax.swing.JComponent.paintToOffscreen(JComponent.java:5131) at javax.swing.BufferStrategyPaintManager.paint(BufferStrategyPaintManager.java:278) at javax.swing.RepaintManager.paint(RepaintManager.java:1224) at javax.swing.JComponent.paint(JComponent.java:1015) at java.awt.GraphicsCallback$PaintCallback.run(GraphicsCallback.java:21) at sun.awt.SunGraphicsCallback.runOneComponent(SunGraphicsCallback.java:60) at sun.awt.SunGraphicsCallback.runComponents(SunGraphicsCallback.java:97) at java.awt.Container.paint(Container.java:1780) at java.awt.Window.paint(Window.java:3375) at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:796) at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:713) at javax.swing.RepaintManager.seqPaintDirtyRegions(RepaintManager.java:693) at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:125) at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209) at java.awt.EventQueue.dispatchEvent(EventQueue.java:597) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161) at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
为什么会这样？
getValueAt 总是返回相同的值来填充所有表条目。 这仅用于调试:
@Override
public Object getValueAt(int rowIndex, int columnIndex) {
return this.EMPTY_ROW;
}
例如，如果我更改为:
@Override
public Object getValueAt(int rowIndex, int columnIndex) {
return new Integer(3);
//or return new Double(3.3);
//return new String("foobar"); doesn't work
}
即使表的某些字段是字符串，也一切正常。它向我暗示，因为 一个 Integer 和一个 Double 可以转换成 String，这不会造成问题。 无论如何，我想了解为什么像我的 EMPTY_ROW 这样的通用对象可以被接受为声明的 Integer 字段的值，而这不适用于 Double 字段。
编辑2:
如果我在表模型中删除 getClass 方法。有用。无论如何，我想在不必删除该方法的情况下解决这个问题，即使这会迫使我实现一些自定义渲染方法。
编辑3:
这是一个 SSCCE。向表中添加新值时出现一些错误，但这与呈现问题无关。
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Comparator;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SortOrder;
import javax.swing.RowSorter.SortKey;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.TableRowSorter;
public class TableExample extends JFrame{
public static final Object EMPTY_ROW = "";
public class EmptyRowComparator<COLUMN_TYPE extends Comparable<COLUMN_TYPE>> implements Comparator<Object>{//extends RuleBasedCollator{
private TableRowSorter<? extends AbstractTableMod> sorter;
private int column;
public EmptyRowComparator(TableRowSorter<? extends AbstractTableMod> sorter, int col) throws ParseException {
// super(arg0);
this.sorter = sorter;
this.column = col;
// TODO Auto-generated constructor stub
}
private int getSortOrder() {
SortOrder order = SortOrder.ASCENDING;
// List<? extends SortKey> keys = sorter.getSortKeys();
// sorter.getSortKeys();
//
for (SortKey sortKey : sorter.getSortKeys()) {
if (sortKey.getColumn() == this.column) {
order = sortKey.getSortOrder();
break;
}
}
return order == SortOrder.ASCENDING ? 1 : -1;
}
@Override
public int hashCode() {
// TODO Auto-generated method stub
return 0;
}
@Override
public int compare(Object arg0, Object arg1) {
// TODO Auto-generated method stub
//System.out.println("Comparing Integer arg0 " + arg0 + " arg1 " + arg1);
boolean empty1 = arg0 == EMPTY_ROW;
boolean empty2 = arg1 == EMPTY_ROW;
if (empty1 && empty2) {
return 0;
}
else if (empty1) {
return 1 * getSortOrder();
}
else if (empty2) {
return -1 * getSortOrder();
}
return ((Comparable<COLUMN_TYPE>) (COLUMN_TYPE)arg0).compareTo((COLUMN_TYPE)arg1);
// return 0;
}
}
public class ConcreteTable extends AbstractTableMod{
//
private static final long serialVersionUID = 4672561280810649603L;
private String[] columnNames = {"ID",
"description"};
Class[] types = {Integer.class, String.class};
//Object[] types = {Double.class, String.class};
private int minimumDisplayedRow;
public ConcreteTable(){
//System.out.println("DEBUG ARRAY length " + data.length);
this.minimumDisplayedRow = 10;
this.datas = new ArrayList<ArrayList<Object>>();
for (int i = 0 ; i < this.minimumDisplayedRow ; i++){
this.addEmptyRow();
}
for (int i = 0 ; i < 5 ; i++){
ArrayList<Object> row = new ArrayList<Object>();
row.add(new Integer(i));
row.add(new String("prova " + i));
this.addRow(row);
}
}
public String getColumnName(int col) {
System.out.println("getColumnName " + col + " = " + columnNames[col]);
return columnNames[col];
}
@Override
protected Class[] getTypeArray() {
// TODO Auto-generated method stub
return this.types;
}
@Override
protected ArrayList<Integer> getKeysColumnIndex() {
// TODO Auto-generated method stub
ArrayList<Integer> keys = new ArrayList<Integer>();
keys.add(0);
return keys;
}
public boolean isCellEditable(int row, int col) {
System.out.println("isCellEditable row " + row + " col " + col);
if (col == 1){
System.out.println("TRUE");
return true;
}
return false;
}
/*note: generated keys must be in the same order they appear in the table*/
@Override
protected Object getGeneratedKeys(int col) {
// TODO Auto-generated method stub
if (col != 0 )
return null;
return new Integer(this.rowNumber);
}
@Override
protected int getMinimumDisplayedRow() {
// TODO Auto-generated method stub
return this.minimumDisplayedRow;
}
}
public abstract class AbstractTableMod extends AbstractTableModel {
ArrayList<ArrayList<Object>> datas ;
protected int rowNumber = 0;
protected abstract Class[] getTypeArray();
protected abstract ArrayList<Integer> getKeysColumnIndex();
protected abstract Object getGeneratedKeys(int col);
protected abstract int getMinimumDisplayedRow();
public int getRowCount(){
return this.datas.size() ;
}
@Override
public int getColumnCount() {
return this.getTypeArray().length;
}
@Override
public Object getValueAt(int rowIndex, int columnIndex) {
if (rowIndex >= this.rowNumber ){
return EMPTY_ROW;
}
try{
ArrayList<Object> row = this.datas.get(rowIndex);
if (row == null)
return null;
Object obj = row.get(columnIndex);
return obj;
}catch(IndexOutOfBoundsException e){
return null;
}
}
public void setValueAt(Object value, int row, int col) {
//System.out.println("setValueAt object : " + value.getClass().getName());
Class<? extends Object> targetColClass = this.getColumnClass(col);
if (!targetColClass.isInstance(value))
return;
if (value instanceof String){
String stringVal = (String)value;
if (stringVal.compareTo("") == 0)
return;
}
if (row >= this.rowNumber){
ArrayList<Object> newRow = new ArrayList<Object>();
ArrayList<Integer> keysIndexList = this.getKeysColumnIndex();
for (int i = 0 ; i < this.getColumnCount(); i++){
if (i == col){
newRow.add(value);
}else if (keysIndexList.contains(i)){
newRow.add(this.getGeneratedKeys(i));
}else{
newRow.add(EMPTY_ROW);
}
}
this.addRow(newRow);
}else{
this.datas.get(row).set(col, value);
}
this.fireTableCellUpdated(row, col);
}
public Class<? extends Object> getColumnClass(int c) {
System.out.println("AbstractTable: getColumnClass");
if (c > this.getTypeArray().length - 1)
return null;
else
return this.getTypeArray()[c];
}
public void addEmptyRow(){
ArrayList<Object> emptyRow = new ArrayList<Object>();
for (int i = 0 ; i < this.getTypeArray().length; i++){
emptyRow.add(EMPTY_ROW);
}
this.datas.add(emptyRow);
}
public void addRow(ArrayList<Object> row){
Object[] types = this.getTypeArray();
if (types.length != row.size())
return;
for (int i = 0 ; i < row.size() ; i++){
Class<? extends Object> targetColClass = this.getColumnClass(i);
Object rowItem = row.get(i);
}
this.datas.add(this.rowNumber, row);
this.rowNumber++;
if (this.rowNumber < this.getMinimumDisplayedRow())
this.datas.remove(this.datas.size() -1 );
this.fireTableRowsInserted(this.rowNumber , this.rowNumber );
}
}
public TableExample(){
super("JTable example");
getContentPane().setLayout(new BoxLayout(getContentPane(), BoxLayout.Y_AXIS));
ConcreteTable model = new ConcreteTable();
JTable tab = new JTable(model);
TableRowSorter<ConcreteTable> sorter = new TableRowSorter<ConcreteTable>(model);
try {
sorter.setComparator(0, new EmptyRowComparator<Integer>(sorter,0));
sorter.setComparator(1, new EmptyRowComparator<String>(sorter,1));
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
tab.setRowSorter(sorter);
JScrollPane table = new JScrollPane(tab);
this.getContentPane().add(table);
this.setSize(600, 400);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setVisible(true);
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
new TableExample();
}
}
如果你尝试改变
Class[] types = {Integer.class, String.class};
与:
Class[] types = {Double.class, String.class};
你可以看出问题所在。
最佳答案
Walter Laan 在他的帖子中是怎么说的
Never give up! Never surrender!
编辑:我无法抗拒，但由于我的英语不好，我不敢评论为什么、在哪里以及如何可能，也不敢正确工作，以确认我为 TableColumnRendering 添加了 Rob 的两个(一点点)修改类。 ..,
import java.awt.EventQueue;
import java.math.RoundingMode;
import java.text.*;
import java.util.*;
import javax.swing.*;
import javax.swing.RowSorter.SortKey;
import javax.swing.SwingConstants;
import javax.swing.table.*;
public class TableExample extends JFrame {
public static final Object EMPTY_ROW = "";
private static final long serialVersionUID = 1L;
private JTable tab;
private Calendar cal;
private Date dateWithOutTime = new java.util.Date();
private SimpleDateFormat sdf = new SimpleDateFormat("dd.MM.yyyy");//standard continental EU date format
public class EmptyRowComparator<COLUMN_TYPE extends Comparable<COLUMN_TYPE>> implements Comparator<Object> {//extends RuleBasedCollator{
private TableRowSorter<? extends AbstractTableMod> sorter;
private int column;
public EmptyRowComparator(TableRowSorter<? extends AbstractTableMod> sorter, int col) throws ParseException {
this.sorter = sorter;
this.column = col;
}
private int getSortOrder() {
SortOrder order = SortOrder.ASCENDING;
for (SortKey sortKey : sorter.getSortKeys()) {
if (sortKey.getColumn() == this.column) {
order = sortKey.getSortOrder();
break;
}
}
return order == SortOrder.ASCENDING ? 1 : -1;
}
@Override
public int hashCode() {
return 0;
}
@Override
@SuppressWarnings("unchecked")
public int compare(Object arg0, Object arg1) {
boolean empty1 = arg0 == EMPTY_ROW;
boolean empty2 = arg1 == EMPTY_ROW;
if (empty1 && empty2) {
return 0;
} else if (empty1) {
return 1 * getSortOrder();
} else if (empty2) {
return -1 * getSortOrder();
}
return ((Comparable<COLUMN_TYPE>) (COLUMN_TYPE) arg0).compareTo((COLUMN_TYPE) arg1);
}
}
public class ConcreteTable extends AbstractTableMod {
private static final long serialVersionUID = 4672561280810649603L;
private String[] columnNames = {"Integer", "String", "Integer", "Double", "Boolean", "Double", "String", "Boolean", "Date"};
private Class<?>[] types = {Integer.class, String.class, String.class, String.class, String.class,
String.class, String.class, String.class, String.class};
private int minimumDisplayedRow;
public ConcreteTable() {
this.minimumDisplayedRow = 10;
this.datas = new ArrayList<ArrayList<Object>>();
for (int i = 0; i < this.minimumDisplayedRow; i++) {
this.addEmptyRow();
}
Random rnd = new Random();
for (int i = 0; i < 7; i++) {
ArrayList<Object> row = new ArrayList<Object>();
row.add(i);
row.add(((rnd.nextInt(25)) + "prova"));
row.add(rnd.nextInt(25));
row.add(rnd.nextInt(25) + 3.14);
row.add((i % 2 == 0) ? true : false);
row.add(rnd.nextInt(25) + 3.14);
row.add(((rnd.nextInt(25)) + "prova"));
row.add((i % 2 == 0) ? false : true);
cal = Calendar.getInstance();
cal.add(Calendar.DATE, -rnd.nextInt(25));
dateWithOutTime = cal.getTime();
String nullTimeForDateString = sdf.format(dateWithOutTime);
try {
dateWithOutTime = sdf.parse(nullTimeForDateString);
} catch (ParseException ex) {
}
row.add(dateWithOutTime);
this.addRow(row);
}
}
@Override
public String getColumnName(int col) {
System.out.println("getColumnName " + col + " = " + columnNames[col]);
return columnNames[col];
}
@Override
protected Class<?>[] getTypeArray() {
return this.types;
}
@Override
protected ArrayList<Integer> getKeysColumnIndex() {
ArrayList<Integer> keys = new ArrayList<Integer>();
keys.add(0);
return keys;
}
@Override
public boolean isCellEditable(int row, int col) {
System.out.println("isCellEditable row " + row + " col " + col);
if (col == 1) {
System.out.println("TRUE");
return true;
}
return false;
}
@Override
protected Object getGeneratedKeys(int col) {
if (col != 0) {
return null;
}
return new Integer(this.rowNumber);
}
@Override
protected int getMinimumDisplayedRow() {
return this.minimumDisplayedRow;
}
}
public abstract class AbstractTableMod extends AbstractTableModel {
private static final long serialVersionUID = 1L;
protected ArrayList<ArrayList<Object>> datas;
protected int rowNumber = 0;
protected abstract Class<?>[] getTypeArray();
protected abstract ArrayList<Integer> getKeysColumnIndex();
protected abstract Object getGeneratedKeys(int col);
protected abstract int getMinimumDisplayedRow();
public int getRowCount() {
return this.datas.size();
}
@Override
public int getColumnCount() {
return this.getTypeArray().length;
}
@Override
public Object getValueAt(int rowIndex, int columnIndex) {
if (rowIndex >= this.rowNumber) {
return EMPTY_ROW;
}
try {
ArrayList<Object> row = this.datas.get(rowIndex);
if (row == null) {
return null;
}
Object obj = row.get(columnIndex);
return obj;
} catch (IndexOutOfBoundsException e) {
return null;
}
}
@Override
public void setValueAt(Object value, int row, int col) {
Class<? extends Object> targetColClass = this.getColumnClass(col);
if (!targetColClass.isInstance(value)) {
return;
}
if (value instanceof String) {
String stringVal = (String) value;
if (stringVal.compareTo("") == 0) {
return;
}
}
if (row >= this.rowNumber) {
ArrayList<Object> newRow = new ArrayList<Object>();
ArrayList<Integer> keysIndexList = this.getKeysColumnIndex();
for (int i = 0; i < this.getColumnCount(); i++) {
if (i == col) {
newRow.add(value);
} else if (keysIndexList.contains(i)) {
newRow.add(this.getGeneratedKeys(i));
} else {
newRow.add(EMPTY_ROW);
}
}
this.addRow(newRow);
} else {
this.datas.get(row).set(col, value);
}
this.fireTableCellUpdated(row, col);
}
@Override
@SuppressWarnings("unchecked")
public Class<? extends Object> getColumnClass(int c) {
if (c > this.getTypeArray().length - 1) {
return null;
} else {
return this.getTypeArray()[c];
}
}
public void addEmptyRow() {
ArrayList<Object> emptyRow = new ArrayList<Object>();
for (int i = 0; i < this.getTypeArray().length; i++) {
emptyRow.add(EMPTY_ROW);
}
this.datas.add(emptyRow);
}
public void addRow(ArrayList<Object> row) {
Object[] types = this.getTypeArray();
if (types.length != row.size()) {
return;
}
for (int i = 0; i < row.size(); i++) {
Class<? extends Object> targetColClass = this.getColumnClass(i);
Object rowItem = row.get(i);
}
this.datas.add(this.rowNumber, row);
this.rowNumber++;
if (this.rowNumber < this.getMinimumDisplayedRow()) {
this.datas.remove(this.datas.size() - 1);
}
this.fireTableRowsInserted(this.rowNumber, this.rowNumber);
}
}
public TableExample() {
super("JTable example");
getContentPane().setLayout(new BoxLayout(getContentPane(), BoxLayout.Y_AXIS));
ConcreteTable model = new ConcreteTable();
tab = new JTable(model);
TableRowSorter<ConcreteTable> sorter = new TableRowSorter<ConcreteTable>(model);
try {
sorter.setComparator(0, new EmptyRowComparator<Integer>(sorter, 0));
sorter.setComparator(1, new EmptyRowComparator<String>(sorter, 1));
sorter.setComparator(2, new EmptyRowComparator<String>(sorter, 2));
sorter.setComparator(3, new EmptyRowComparator<String>(sorter, 3));
sorter.setComparator(4, new EmptyRowComparator<String>(sorter, 4));
sorter.setComparator(5, new EmptyRowComparator<String>(sorter, 5));
sorter.setComparator(6, new EmptyRowComparator<String>(sorter, 6));
sorter.setComparator(7, new EmptyRowComparator<String>(sorter, 7));
sorter.setComparator(8, new EmptyRowComparator<String>(sorter, 8));
} catch (ParseException e) {
e.printStackTrace();
}
tab.setRowSorter(sorter);
JScrollPane table = new JScrollPane(tab);
this.getContentPane().add(table);
this.setSize(800, 400);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setRenderers();
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
setVisible(true);
}
});
//TableExample tableExample = new TableExample();
}
public void setRenderers() {
TableColumnModel m = tab.getColumnModel();
//"Integer", "String", "Interger", "Double", "Boolean", "Double", "String", "Boolean", "Date"
m.getColumn(0).setCellRenderer(NumberRenderer.getIntegerRenderer());
m.getColumn(2).setCellRenderer(NumberRenderer.getIntegerRenderer());
m.getColumn(3).setCellRenderer(NumberRenderer.getDoubleRenderer5());
m.getColumn(5).setCellRenderer(NumberRenderer.getDoubleRenderer3());
m.getColumn(8).setCellRenderer(FormatRenderer.getDateRenderer());
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
TableExample tableExample = new TableExample();
}
});
TableExample tableExample = new TableExample();
}
}
class FormatRenderer extends DefaultTableCellRenderer {
private static final long serialVersionUID = 1L;
private Format formatter;
private static DateFormat dateFormat = new SimpleDateFormat("dd.MM.yyyy");//standard continental EU date format
FormatRenderer(Format formatter) {
this.formatter = formatter;
}
@Override
public void setValue(Object value) {
try {
if ((value != null)) {
if ((value instanceof Number) || (value instanceof Date)) {
setHorizontalAlignment(SwingConstants.RIGHT);
value = formatter.format(value);
}
}
} catch (IllegalArgumentException e) {
}
super.setValue(value);
}
public static FormatRenderer getDateRenderer() {
return new FormatRenderer(dateFormat);
}
}
class NumberRenderer extends FormatRenderer {
private static final long serialVersionUID = 1L;
private static Number numberValue;
private static NumberFormat nf;
NumberRenderer(NumberFormat formatter) {
super(formatter);
setHorizontalAlignment(SwingConstants.RIGHT);
}
public static NumberRenderer getIntegerRenderer() {
return new NumberRenderer(NumberFormat.getIntegerInstance());
}
public static NumberRenderer getDoubleRenderer3() {
nf = NumberFormat.getNumberInstance();
nf.setMinimumFractionDigits(3);
nf.setMaximumFractionDigits(3);
nf.setRoundingMode(RoundingMode.HALF_UP);
return new NumberRenderer(nf);
}
public static NumberRenderer getDoubleRenderer5() {
nf = NumberFormat.getNumberInstance();
nf.setMinimumFractionDigits(5);
nf.setMaximumFractionDigits(5);
nf.setRoundingMode(RoundingMode.HALF_UP);
return new NumberRenderer(nf);
}
}
关于java - JTable 中的问题格式化字段 - Integer 和 Double 之间的区别，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/6187566/