本文目錄一覽：
java編寫的記事本的保存和另存為功能
可以通過「FileOutputStream」創建文件實例，之後過「OutputStreamWriter」流的形式進行存儲，舉例：
OutputStreamWriter
pw
=
null;//定義一個流
pw
=
new
OutputStreamWriter(new
FileOutputStream(「D:/test.txt」),”GBK”);//確認流的輸出文件和編碼格式，此過程創建了「test.txt」實例
pw.write(“我是要寫入到記事本文件的內容”);//將要寫入文件的內容，可以多次write
pw.close();//關閉流
解釋：文件流用完之後必須及時通過close方法關閉，否則會一直處於打開狀態，直至程序停止，增加系統負擔。
如何用JAVA程序編寫一個記事本
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.undo.CannotRedoException;
import javax.swing.undo.UndoManager;
import java.util.Date;
import java.text.SimpleDateFormat;
public class Notepad extends JFrame {
// 菜單
JMenuBar menub = new JMenuBar();
// 顯示純文本的多行區域
JTextArea text = new JTextArea();
JMenu files = new JMenu(“文件(F)”);
JMenu edit = new JMenu(“編輯(E)”);
JMenu formats = new JMenu(“格式(O)”);
JMenu help = new JMenu(“幫助(H)”);
JMenuItem newFile = new JMenuItem(“新建(N)”);
JMenuItem open = new JMenuItem(“打開(O)”);
JMenuItem save = new JMenuItem(“保存(S)”);
JMenuItem saveAs = new JMenuItem(“另存為(A)”);
JMenuItem exit = new JMenuItem(“退出(X)”);
JMenuItem undo = new JMenuItem(“撤銷(U)”);
JMenuItem cut = new JMenuItem(“剪切(T)”);
JMenuItem copy = new JMenuItem(“複製(C)”);
JMenuItem paste = new JMenuItem(“粘貼(P)”);
JMenuItem selectAll = new JMenuItem(“全選(A)”);
JMenuItem timeDate = new JMenuItem(“時間/日期(D)”);
JCheckBoxMenuItem lineWrap = new JCheckBoxMenuItem(“自動換行(M)”);
JMenuItem fonts = new JMenuItem(“字體”);
JMenuItem about = new JMenuItem(“關於記事本(A)”);
JFrame th = this;
String name;
String openedPath = null;
boolean opened = false;
boolean reworked = false;
UndoManager undoManager = new UndoManager();
// 初始化窗體
public Notepad(String name) {
super(name);
this.name = name;
int x, y;
// 得到用戶屏幕大小
Dimension size = Toolkit.getDefaultToolkit().getScreenSize();
x = (size.width – 600) / 2;
y = (size.height – 400) / 2;
setSize(600, 400);
// 讓程序界面顯示在屏幕中央
setLocation(x, y);
// 將此窗口的最小大小設置為一個常量值。
setMinimumSize(new Dimension(250, 150));
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
// 初始化布局
void init() {
files.setMnemonic(‘F’);
edit.setMnemonic(‘E’);
formats.setMnemonic(‘O’);
help.setMnemonic(‘H’);
newFile.setMnemonic(‘N’);
open.setMnemonic(‘O’);
save.setMnemonic(‘S’);
saveAs.setMnemonic(‘A’);
exit.setMnemonic(‘X’);
undo.setMnemonic(‘U’);
cut.setMnemonic(‘T’);
copy.setMnemonic(‘C’);
paste.setMnemonic(‘P’);
selectAll.setMnemonic(‘A’);
timeDate.setMnemonic(‘D’);
lineWrap.setMnemonic(‘M’);
about.setMnemonic(‘A’);
// 為控件添加助記符
newFile.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_N,
InputEvent.CTRL_MASK));
open.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_O,
InputEvent.CTRL_MASK));
save.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S,
InputEvent.CTRL_MASK));
exit.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_Q,
InputEvent.CTRL_MASK));
cut.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_X,
InputEvent.CTRL_MASK));
copy.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_C,
InputEvent.CTRL_MASK));
paste.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_V,
InputEvent.CTRL_MASK));
selectAll.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_A,
InputEvent.CTRL_MASK));
// 為控件添加快捷鍵
timeDate.setAccelerator(KeyStroke.getKeyStroke(“F5”));
files.add(newFile);
files.add(open);
files.add(save);
files.add(saveAs);
files.addSeparator();
files.add(exit);
edit.add(undo);
edit.addSeparator();
edit.add(cut);
edit.add(copy);
edit.add(paste);
edit.addSeparator();
edit.add(selectAll);
edit.add(timeDate);
formats.add(lineWrap);
formats.add(fonts);
help.add(about);
menub.add(files);
menub.add(edit);
menub.add(formats);
menub.add(help);
setJMenuBar(menub);
getContentPane().add(new JScrollPane(text));
Listen listen = new Listen();
Listen1 listen1 = new Listen1();
// 為控件添加事件偵聽器
newFile.addActionListener(listen);
undo.addActionListener(listen);
open.addActionListener(listen);
save.addActionListener(listen);
saveAs.addActionListener(listen);
exit.addActionListener(listen);
cut.addActionListener(listen);
copy.addActionListener(listen);
paste.addActionListener(listen);
selectAll.addActionListener(listen);
timeDate.addActionListener(listen);
lineWrap.addActionListener(listen);
about.addActionListener(listen);
open.addActionListener(listen1);
save.addActionListener(listen1);
saveAs.addActionListener(listen1);
// 暫時沒有實現的功能 :設置字體
//undo功能沒有實現
fonts.setEnabled(false);
}
class Listen implements ActionListener {
// 實現用於一般操作的事件偵聽器
public void actionPerformed(ActionEvent e) {
Object source = e.getSource();
if (source == newFile) {
text.setText(“”);
// 設置標題
th.setTitle(name);
openedPath = null;
opened = false;
} else if (source == exit)
setVisible(false);
else if (source == undo)
try {
//此功能沒有實現 撤銷要用棧？
// undo.setEnabled(undoManager.canUndo());
undoManager.undo();
} catch (CannotRedoException cre) {
cre.printStackTrace();
}
else if (source == selectAll)
text.selectAll();
else if (source == cut)
text.cut();
else if (source == copy)
text.copy();
else if (source == paste)
text.paste();
else if (source == lineWrap)
// 設置文本區的換行策略(獲取文本區的換行策略)
text.setLineWrap(!text.getLineWrap());
else if (source == about) {
String message = “——–\n版本：1.0\n作者：時超” +
“\n撤銷功能要用堆棧存貯操作” +
“\n還有字體格式”+
“\n暫時沒有實現” +
“\n\n感謝您的使用”;
JOptionPane.showMessageDialog(th, message, “關於”,
JOptionPane.PLAIN_MESSAGE);
} else if (source == timeDate) {
Date nowTime = new Date();
SimpleDateFormat times = new SimpleDateFormat(
“HH:mm yyyy-MM-dd”);
text.insert(times.format(nowTime), text.getCaretPosition());
}
}
}
class Listen1 implements ActionListener {
// 實現用於對文件進行操作的事件偵聽器
public void actionPerformed(ActionEvent e) {
Object source = e.getSource();
// 打開文件事件
if (source == open) {
// 顯示對話窗口 以便選擇文件
FileDialog openFile = new FileDialog(th, “打開文件”,
FileDialog.LOAD);
openFile.setVisible(true);
// 獲取文件路徑
String filePath = openFile.getDirectory() + openFile.getFile();
try {
FileInputStream fis = new FileInputStream(filePath);
byte[] content = new byte[fis.available()];
fis.read(content);
text.setText(new String(content));
// 設置 TextComponent 的文本插入符的位置
text.setCaretPosition(0);
if (openFile.getFile() != null) {
th.setTitle(openFile.getFile() + name);
openedPath = filePath;
opened = true;
}
fis.close();
} catch (Exception ex) {
ex.printStackTrace();
}
opened = true;
}
// 保存及另存為事件
else if (source == save || source == saveAs) {
String savePath = openedPath;
if (savePath == null || source == saveAs) {
// 如果 mode 的值為 LOAD，那麼文件對話框將查找要讀取的文件，所顯示的文件是當前目錄中的文件
// 如果 mode 的值為 SAVE，則文件對話框將查找要寫入文件的位置。
FileDialog saveFile = new FileDialog(th, “保存文件”,
FileDialog.SAVE);
saveFile.setVisible(true);
savePath = saveFile.getDirectory() + saveFile.getFile();
}
try {
FileOutputStream fos = new FileOutputStream(savePath);
fos.write(text.getText().getBytes());
fos.close();
} catch (Exception ex) {
ex.printStackTrace();
}
if (source == save)
openedPath = savePath;
}
}
}
public static void main(String[] args) {
try {
// 使用當前線程的上下文類加載器加載給定類名稱所指定的 LookAndFeel
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception e) {
System.err.println(“Couldn’t use the system look and feel:” + e);
}
String name = (“–記事本 版本1.0–“);
Notepad note = new Notepad(name);
note.init();
note.setVisible(true);
}
}
如何用JAVA編寫簡單的記事本程序？
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.io.*;
import java.awt.datatransfer.*;public class NewEdit
{
public static void main(String args[])
{
MyFrame EditFrame=new MyFrame();
EditFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
EditFrame.setVisible(true);
}
}class MyFrame extends JFrame
{
public MyFrame()
{ Dimension screenSize=toolKit.getScreenSize();
int screenHeight=screenSize.height;
int screenWidth=screenSize.width;
setSize(screenWidth/2,screenHeight/2);
setLocation(screenWidth/4,screenHeight/4);
Image img=toolKit.getImage(“icon.gif”);
setIconImage(img);
setTitle(“MyEdit”);
JMenuBar menuBar=new JMenuBar();
setJMenuBar(menuBar);
JMenu fileMenu=new JMenu(“文件”);
JMenu editMenu=new JMenu(“編輯”);
JMenu helpMenu=new JMenu(“幫助”);
menuBar.add(fileMenu);
menuBar.add(editMenu);
menuBar.add(helpMenu);
JMenuItem newItem=new JMenuItem(“新建”);
newItem.addActionListener(new NewListener());
JMenuItem openItem=new JMenuItem(“打開”);
openItem.addActionListener(new OpenListener());
JMenuItem saveItem=new JMenuItem(“保存”);
saveItem.addActionListener(new SaveListener());
JMenuItem escItem=new JMenuItem(“退出”);
escItem.addActionListener(new
ActionListener()
{
public void actionPerformed(ActionEvent myE)
{
System.exit(0);
}
});
fileMenu.add(newItem);
fileMenu.add(openItem);
fileMenu.add(saveItem);
fileMenu.add(escItem);
JMenuItem allItem=new JMenuItem(“全選”);
//JMenuItem copyItem=new JMenuItem(“複製”);
//CopyAction copyAction=new CopyAction();
//copyItem.addActionListener(copyAction);
JMenuItem cutItem=new JMenuItem(“剪切”);
//JMenuItem pasteItem=new JMenuItem(“粘貼”);
//Action pasteAction=new PasteAction();
//pasteItem.addActionListener(pasteAction);
editMenu.add(allItem);
allItem.addActionListener(new
ActionListener()
{
public void actionPerformed(ActionEvent myE)
{
textArea.selectAll();
}
});
CopyAction copyAction=new CopyAction(“剪切”);
editMenu.add(copyAction);
CutAction cutAction=new CutAction(“複製”);
editMenu.add(cutAction);
Action pasteAction=new PasteAction(“粘貼”);
editMenu.add(pasteAction);
popup=new JPopupMenu();
popup.add(copyAction);
popup.add(pasteAction);
popup.add(cutAction);
textArea = new JTextArea();
textArea.add(popup);
textArea.addMouseListener(new
MouseListener(){
public void mouseClicked(MouseEvent e) {} public void mouseEntered(MouseEvent e) {} public void mouseExited(MouseEvent e) {} public void mousePressed(MouseEvent e) {
if (e.getButton() == MouseEvent.BUTTON3)
{
popup.show(textArea, e.getX(), e.getY());
}
} public void mouseReleased(MouseEvent e) {} });//可嘗試用MouseAdapter,代碼可能更簡單
JScrollPane scroller = new JScrollPane(textArea);
add(scroller);
//OR–this.getContentPane().add(scroller)
//scroller.setComponentPopupMenu(popup);
//textArea.setInheritsPopupMenu(true);
//scroller.addMouseListener(new MouseAdapter(){});
}
public void writeFile(String fileName)
{
try
{
File file = new File(fileName);
FileWriter write = new FileWriter(file);
write.write(textArea.getText());
write.close();
}
catch(Exception e){
System.out.println(“Error closing file!”);
}
}
public void openFile(String fileName)
{
try
{
File file = new File(fileName);
FileReader readIn = new FileReader(file);
int size = (int)file.length();
int charsRead = 0;
char[] content = new char[size];
while(readIn.ready())
charsRead += readIn.read(content,charsRead,size-charsRead);
readIn.close();
textArea.setText(new String(content,0,charsRead));
}
catch(IOException e)
{
System.out.println(“Error opening file!”);
}
}
private class NewListener implements ActionListener
{
public void actionPerformed(ActionEvent myE)
{
textArea.setText(“”);
}
}
private class OpenListener implements ActionListener
{
public void actionPerformed(ActionEvent myE)
{
openFileDialog.setVisible(true);
fileName = openFileDialog.getDirectory()+openFileDialog.getFile();
if(fileName != null)
{
openFile(fileName);
}
}
}
private class SaveListener implements ActionListener
{
public void actionPerformed(ActionEvent myE)
{
saveFileDialog.setVisible(true);
fileName = saveFileDialog.getDirectory()+saveFileDialog.getFile();
if(fileName !=null)
{
writeFile(fileName);
}
}
}
private class CutAction extends AbstractAction
{
public CutAction(String name)
{
super(name);
}
public void actionPerformed(ActionEvent event)
{
String text = textArea.getSelectedText();
StringSelection selection = new StringSelection(text);
clipboard.setContents(selection,null);
textArea.replaceRange(“”,textArea.getSelectionStart(),
textArea.getSelectionEnd());
}
}
private class CopyAction extends AbstractAction
{
public CopyAction(String name)
{
super(name);
}
public void actionPerformed(ActionEvent event)
{
String text = textArea.getSelectedText();
StringSelection selection= new StringSelection(text);
clipboard.setContents(selection,null);
}
}
private class PasteAction extends AbstractAction
{
public PasteAction(String name)
{
super(name);
}
public void actionPerformed(ActionEvent event)
{
Transferable contents = clipboard.getContents(this);
if(contents==null)
return;
String text;
text=””;
try
{
text = (String)contents.getTransferData(DataFlavor.stringFlavor);
}
catch(Exception ex){}
textArea.replaceRange(text,
textArea.getSelectionStart(),textArea.getSelectionEnd());
}
}
private JTextArea textArea;
private JPopupMenu popup;
private String fileName=””;
private FileDialog openFileDialog=new FileDialog(this,”OpenFile”,FileDialog.LOAD); private FileDialog saveFileDialog=new FileDialog(this,”SaveFile”,FileDialog.SAVE);
Toolkit toolKit = Toolkit.getDefaultToolkit();
private Clipboard clipboard = toolKit.getSystemClipboard();}
原創文章，作者：小藍，如若轉載，請註明出處：https://www.506064.com/zh-hk/n/295662.html
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