我已經(jīng)擁有的是一個(gè)JTable附有MyTableModel表格模型的表格。我有一種在修改表格單元格時(shí)tableChanged()將表格數(shù)據(jù)寫入data.csv文件的方法。這意味著每次用戶輸入新數(shù)據(jù)時(shí)都會(huì)將表數(shù)據(jù)寫入文件。相反，我希望有一個(gè)菜單項(xiàng)，用戶單擊“保存”，然后繼續(xù)執(zhí)行保存到文件的代碼。@Overridepublic void tableChanged(TableModelEvent e) { int row = e.getFirstRow(); int column = e.getColumn(); TableModel model = (TableModel) e.getSource(); String columnName = model.getColumnName(column); Object data = model.getValueAt(row, column); BufferedWriter bw = null; FileWriter fw = null; String rivi = ""; try { fw = new FileWriter("data.csv"); bw = new BufferedWriter(fw); for (int i = 0; i < model.getRowCount(); i++) { for (int j = 0; j < model.getColumnCount(); j++) { if (j == 69) { rivi += model.getValueAt(i, j); } else { rivi += model.getValueAt(i, j) + ","; } } if (i != 69) { rivi += "\n"; } } bw.write(rivi); } catch (Exception ex) { ex.printStackTrace(); } finally { try { if (bw != null) { bw.close(); } if (fw != null) { fw.close(); } } catch (Exception ex) { ex.printStackTrace(); } }}假設(shè)我理解正確，我需要的是將文件保存代碼從tableChanged()方法移動(dòng)到actionPerformed()方法，但我不知道如何TableModelEvent e從方法中獲取參數(shù)tableChanged()并在方法中使用它actionPerformed()，以便我可以獲得表數(shù)據(jù)通過TableModel model = (TableModel) e.getSource()并將其保存到文件中。@Overridepublic void actionPerformed(ActionEvent e) { // File saving code here?}
1 回答
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TA貢獻(xiàn)1942條經(jīng)驗(yàn) 獲得超3個(gè)贊
您的代碼正在運(yùn)行，而您的問題更為基本——您正在創(chuàng)建太多DesktopEsimerkki對(duì)象，其中一個(gè)您正在更改其值，而另一個(gè)您正在顯示其值。改變這個(gè)：
JFrame frame = new JFrame("DesktopEsimerkki");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// this guy creates the menu
DesktopEsimerkki desim = new DesktopEsimerkki();
frame.setJMenuBar(desim.luoValikkoPalkki());
// but this separate guy is used as the GUI
DesktopEsimerkki newContentPane = new DesktopEsimerkki();
newContentPane.setOpaque(true);
frame.setContentPane(newContentPane);
對(duì)此：
JFrame frame = new JFrame("DesktopEsimerkki");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// use only one instance for **both**
DesktopEsimerkki desim = new DesktopEsimerkki();
frame.setJMenuBar(desim.luoValikkoPalkki());
// DesktopEsimerkki newContentPane = new DesktopEsimerkki();
// newContentPane.setOpaque(true);
// frame.setContentPane(newContentPane);
// *********** here ***********
frame.setContentPane(desim);
只是為了笑，我創(chuàng)建了自己的程序來執(zhí)行此操作，例如：
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Formatter;
import java.util.Scanner;
import javax.swing.*;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
@SuppressWarnings("serial")
public class TableFun extends JPanel {
public static final String DATA_FILE_PATH = "data.csv";
private MyTableModel model = new MyTableModel();
private JTable table = new JTable(model);
private JTextField fileNameField = new JTextField(DATA_FILE_PATH, 30);
private JMenuBar menuBar;
private Action writeModelAction = new WriteModelAction(table, "Write to File", this);
private Action readModelAction = new ReadModelAction(table, "Read from File", this);
public TableFun() {
JPanel btnPanel = new JPanel();
btnPanel.add(new JLabel("File:"));
btnPanel.add(fileNameField);
btnPanel.add(new JButton(writeModelAction));
btnPanel.add(new JButton(readModelAction));
table.getColumnModel().getColumn(0).setCellRenderer(new TimeColumnRenderer());
JScrollPane scrollpane = new JScrollPane(table);
setLayout(new BorderLayout());
add(scrollpane);
add(btnPanel, BorderLayout.PAGE_START);
}
public String getFileName() {
return fileNameField.getText();
}
public JMenuBar getMenuBar() {
if (menuBar == null) {
menuBar = new JMenuBar();
JMenu fileMenu = new JMenu("File");
fileMenu.setMnemonic(KeyEvent.VK_F);
menuBar.add(fileMenu);
fileMenu.add(new JMenuItem(readModelAction));
fileMenu.add(new JMenuItem(writeModelAction));
}
return menuBar;
}
private static void createAndShowGui() {
TableFun mainPanel = new TableFun();
JFrame frame = new JFrame("TableFun");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.setJMenuBar(mainPanel.getMenuBar());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
@SuppressWarnings("serial")
class WriteModelAction extends AbstractAction {
private ReadWriteTableData readWriteTableData;
private TableFun tableFun;
public WriteModelAction(JTable table, String name, TableFun tableFun) {
super(name);
int mnemonic = name.charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
readWriteTableData = new ReadWriteTableData(table);
this.tableFun = tableFun;
}
@Override
public void actionPerformed(ActionEvent e) {
File file = new File(tableFun.getFileName());
if (file.exists()) {
String message = "File " + tableFun.getFileName() + " already exists -- do you wish to overrite?";
String title = "File Already Exists";
int optionType = JOptionPane.YES_NO_OPTION;
int response = JOptionPane.showConfirmDialog(tableFun, message, title, optionType);
if (response != JOptionPane.YES_OPTION) {
return;
}
}
try {
readWriteTableData.write(file);
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
@SuppressWarnings("serial")
class ReadModelAction extends AbstractAction {
private ReadWriteTableData readWriteTableData;
private TableFun tableFun;
public ReadModelAction(JTable table, String name, TableFun tableFun) {
super(name);
int mnemonic = name.charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
readWriteTableData = new ReadWriteTableData(table);
this.tableFun = tableFun;
}
@Override
public void actionPerformed(ActionEvent e) {
File file = new File(tableFun.getFileName());
if (!file.exists()) {
String message = "File " + tableFun.getFileName() + " cannot be found -- aborting read";
String title = "File Cannot Be Found";
int optionType = JOptionPane.WARNING_MESSAGE;
JOptionPane.showMessageDialog(tableFun, message, title, optionType);
return;
}
try {
readWriteTableData.read(file);
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
class ReadWriteTableData {
private JTable table;
public ReadWriteTableData(JTable table) {
this.table = table;
}
public void read(File file) throws FileNotFoundException {
MyTableModel tableModel = (MyTableModel) table.getModel();
tableModel.setRowCount(0);
Scanner scanner = new Scanner(file);
while (scanner.hasNextLine()) {
String line = scanner.nextLine().trim();
if (!line.isEmpty()) {
String[] tokens = line.split("\\|");
String[] trimmedTokens = new String[tokens.length];
for (int i = 0; i < tokens.length; i++) {
String text = tokens[i];
if (text == null || text.trim().equals("null")) {
text = "";
} else {
text = text.trim();
}
trimmedTokens[i] = text;
}
tableModel.addRow(trimmedTokens);
}
}
table.setModel(tableModel);
scanner.close();
}
public void write(File file) throws IOException {
FileWriter fileWriter = new FileWriter(file);
Formatter formatter = new Formatter(fileWriter);
MyTableModel model = (MyTableModel) table.getModel();
for (int row = 0; row < model.getRowCount(); row++) {
for (int col = 0; col < model.getColumnCount(); col++) {
String value = (String) model.getValueAt(row, col);
value = value == null ? "" : value;
formatter.format("%25s ", value);
if (col != model.getColumnCount() - 1) {
formatter.format(" | ");
}
}
formatter.format("%n");
}
if (formatter != null) {
formatter.close();
}
}
}
class MyTableModel extends DefaultTableModel {
public static final String[] COLUMNS = {"Time", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday"};
private static final int START_TIME = 8;
private static final int END_TIME = 17;
public MyTableModel() {
super(COLUMNS, 0);
for (int i = START_TIME; i < END_TIME + 1; i++) {
Object[] rowData = {String.valueOf(i), "", "", "", "", ""};
addRow(rowData);
}
}
@Override
public boolean isCellEditable(int row, int column) {
return column != 0;
}
}
class TimeColumnRenderer extends DefaultTableCellRenderer {
public TimeColumnRenderer() {
setHorizontalAlignment(SwingConstants.TRAILING);
}
@Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected,
boolean hasFocus, int row, int column) {
int time = Integer.parseInt(value.toString());
time = time > 12 ? time % 12 : time;
String timeText = String.format("%d:00", time);
return super.getTableCellRendererComponent(table, timeText, isSelected, hasFocus, row, column);
}
}
它使用管道符號(hào)|作為 csv 分隔符，因此典型的文本文件可能如下所示：
8 | | judy | | |
9 | John | | Bill | | Frank
10 | | Hello | | Goodbye |
11 | Donald duck | Frank Nitti | Al Capone | Johnson |
12 | | | | | ss
13 | | | | |
14 | Bill Clinton | Donald Trump | Hello | Fresh |
15 | | What the | heck | | Yes
16 | | | | |
17 | Here | we |
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