Java学习笔记——文本操作(记事本实现)

import java.awt.FileDialog;
import java.awt.GridLayout;
import java.awt.Toolkit;
import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.StringSelection;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.event.*;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.Writer;

import javax.swing.*;
import javax.swing.event.*;
import javax.swing.filechooser.FileNameExtensionFilter;
import javax.swing.undo.UndoManager;
/*
* 记事本----独孤我---2011年12月5日----绿岛网络办公室
* 转载请注明出处*
*
* */

public class Notepad extends JFrame implements ActionListener
{
/**
*
*/
private static final long serialVersionUID = 1L;
JPanel pl=new JPanel();
JTextArea myarea=new JTextArea();

//相关变量
int start=0;//查找开始位置
int end=0;//查找结束位置
private String filename; //打开的文件名
String textContent="";//编辑框中的内容
private Writer file_writer;
UndoManager undoManager = new UndoManager();//撤销管理器

public Notepad()
{
initComponment();//面板初始化
}
private void initComponment()
{
//菜单栏
JMenuBar mb=new JMenuBar();

//弹出菜单
final JPopupMenu myPopMenu=new JPopupMenu();
JMenuItem copy_pop=new JMenuItem("复制");
JMenuItem cut_pop=new JMenuItem("剪切");
JMenuItem paste_pop=new JMenuItem("粘贴");
JMenuItem delete_pop=new JMenuItem("删除");
JMenuItem exit_pop=new JMenuItem("退出");

myPopMenu.add(cut_pop);
myPopMenu.add(copy_pop);
myPopMenu.add(delete_pop);
myPopMenu.add(paste_pop);
myPopMenu.add(exit_pop);

cut_pop.addActionListener(this);
copy_pop.addActionListener(this);
delete_pop.addActionListener(this);
paste_pop.addActionListener(this);
exit_pop.addActionListener(this);

//菜单
JMenu file=new JMenu("文件");
JMenu edit=new JMenu("编辑");
JMenu help=new JMenu("帮助");

//子菜单
JMenuItem new_file=new JMenuItem("新建");
JMenuItem open=new JMenuItem("打开");
JMenuItem save=new JMenuItem("保存");
JMenuItem save_as=new JMenuItem("另存为");
JMenuItem exit=new JMenuItem("退出");

JMenuItem search=new JMenuItem("查找和替换");

JMenuItem copy=new JMenuItem("复制");
JMenuItem cut=new JMenuItem("剪切");
JMenuItem paste=new JMenuItem("粘贴");
JMenuItem delete=new JMenuItem("删除");

//绑定监听事件
new_file.addActionListener(this);
open.addActionListener(this);
save.addActionListener(this);
save_as.addActionListener(this);
exit.addActionListener(this);

copy.addActionListener(this);
cut.addActionListener(this);
paste.addActionListener(this);
delete.addActionListener(this);
search.addActionListener(this);

//将菜单和相应的子菜单添加到菜单栏
file.add(open);
file.add(new_file);
file.add(save);
file.add(save_as);
file.addSeparator();
file.add(exit);

edit.add(copy);
edit.add(cut);
edit.add(paste);
edit.add(delete);
edit.add(search);

mb.add(file);
mb.add(edit);
mb.add(help);

//给文本区域添加滚动条
myarea.add(myPopMenu);
JScrollPane scrollpane=new JScrollPane(myarea);
//主窗口
setTitle("记事本");
setSize(600,400);
setLocation(400,300);

setJMenuBar(mb);
//add("Center",myarea);
add(scrollpane);
// add(myPopMenu);

//窗口监听
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent evt)
{
if(!myarea.getText().equals(textContent))
{
int result=JOptionPane.showConfirmDialog(null,"文件内容已改变，确认保存退出吗？","警告",1);
if(result==JOptionPane.OK_OPTION)
{
save();
System.exit(0);
}
}
else
System.exit(0);
}
});
//鼠标监听
myarea.addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent e)
{
int mods=e.getModifiers();
//鼠标右键
if((mods&InputEvent.BUTTON3_MASK)!=0){
//弹出菜单
myPopMenu.show(e.getComponent(),e.getX(),e.getY());
}
}

});

}
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
try
{
if(e.getActionCommand()=="新建")
{
myarea.setText("");
}
else if(e.getActionCommand()=="打开")
{
FileDialog fileDialog=new FileDialog(this,"打开文件",FileDialog.LOAD);
fileDialog.setFile("*.txt");
fileDialog.setVisible(true);
if(fileDialog.getFile()!=null)
{
filename=fileDialog.getDirectory()+fileDialog.getFile();//获得文件名

//读取文件

FileReader file_reader=new FileReader(filename);//此处必须要捕获异常
BufferedReader br=new BufferedReader(file_reader);
String temp="";
while(br.ready())//判断缓冲区是否为空，非空时返回true
{
int c=br.read();
temp+=(char)c;
}
myarea.setText(temp);
br.close();
file_reader.close();
textContent=myarea.getText();
setTitle("记事本-"+filename);

}
}
else if(e.getActionCommand()=="保存")
{
save();
}
else if(e.getActionCommand()=="另存为")
{
FileDialog fileDialog=new FileDialog(this,"另存为",FileDialog.SAVE);
fileDialog.setFile("*.txt");
fileDialog.setVisible(true);
if(fileDialog.getFile()!=null)               {

//File temp=new File(file.getAbsolutePath()+".txt");
//file.renameTo(temp);
//写入文件
FileWriter fw=new FileWriter(fileDialog.getDirectory()+fileDialog.getFile());
BufferedWriter bw=new BufferedWriter(fw);
PrintWriter pw=new PrintWriter(bw);
pw.print(myarea.getText());
textContent=myarea.getText();
pw.close();
bw.close();
fw.close();

}
}
else if(e.getActionCommand()=="退出")
{
if(!myarea.getText().equals(textContent))
{
int result=JOptionPane.showConfirmDialog(null,"文件内容已改变，确认保存退出吗？","警告",1);
if(result==JOptionPane.OK_OPTION)
{
save();
System.exit(0);
}
}
else
System.exit(0);
}
else if(e.getActionCommand()=="查找和替换")
{
//查找对话框
JDialog search=new JDialog(this,"查找和替换");
search.setSize(200, 100);
search.setLocation(450,350);
JLabel label_1=new JLabel("查找的内容");
JLabel label_2=new JLabel("替换的内容");
final JTextField textField_1=new JTextField(5);
final JTextField textField_2=new JTextField(5);
JButton buttonFind=new JButton("查找下一个");
JButton buttonChange=new JButton("替换");
JPanel panel=new JPanel(new GridLayout(2,3));
panel.add(label_1);
panel.add(textField_1);
panel.add(buttonFind);
panel.add(label_2);
panel.add(textField_2);
panel.add(buttonChange);
search.add(panel);
search.setVisible(true);

//为查找下一个 按钮绑定监听事件
buttonFind.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String findText=textField_1.getText();//查找的字符串

String textArea=myarea.getText();//当前文本框的内容
start=textArea.indexOf(findText,end);
end=start+findText.length();
if(start==-1)//没有找到
{
JOptionPane.showMessageDialog(null,"没找到"+findText,"记事本",JOptionPane.WARNING_MESSAGE);
myarea.select(start, end);
}
else
{
myarea.select(start,end);
}

}
});
//为替换按钮绑定监听时间
buttonChange.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String changeText=textField_2.getText();//替换的字符串
myarea.select(start, end);
myarea.replaceSelection(changeText);
myarea.select(start, end);
}
});

}
else if(e.getActionCommand()=="复制")
{
copy();
}
else if(e.getActionCommand()=="粘贴")
{
paste();
}
else if(e.getActionCommand()=="剪切")
{
cut();
}
else if(e.getActionCommand()=="删除")
{
delete();
}
}
catch(Exception ex)
{
ex.printStackTrace();
}

}
public static void main(String[] args)
{
new Notepad().setVisible(true);
}
private void save()
{
try
{
File file=new File(filename);
FileWriter file_writer;

file_writer = new FileWriter(file);

BufferedWriter bw=new BufferedWriter(file_writer);
PrintWriter pw=new PrintWriter(bw);//如果直接向文件中输入而不是输入缓冲区，效率低下

pw.print(myarea.getText());
textContent=myarea.getText();
pw.close();
bw.close();
file_writer.close();
}
catch(Exception e)
{
e.printStackTrace();
}
}
private void cut()
{
copy();
delete();
}
private void copy()
{
if(myarea.getSelectedText()==null)
{
JOptionPane.showMessageDialog(null, "你没有选中任何文字！","记事本",JOptionPane.WARNING_MESSAGE);
}
Clipboard clipBoard= Toolkit.getDefaultToolkit().getSystemClipboard();
StringSelection stringSelection=new StringSelection(myarea.getSelectedText());
clipBoard.setContents(stringSelection, null);
}
private void paste() throws UnsupportedFlavorException, IOException
{
String content_copy="";
//构造系统剪切板
Clipboard clipBoard= Toolkit.getDefaultToolkit().getSystemClipboard();

//获取剪切板内容
Transferable content=clipBoard.getContents(null);

if(content!=null)
{
//检查是否是文本类型
if(content.isDataFlavorSupported(DataFlavor.stringFlavor))
{
content_copy=(String) content.getTransferData(DataFlavor.stringFlavor);

//判断文本框中有无文字选中
if(myarea.getSelectedText()!=null)
{
myarea.replaceSelection(content_copy);
}
else
{
myarea.insert(content_copy, myarea.getSelectionStart());
}
}
}
else
JOptionPane.showMessageDialog(null, "系统剪贴板中无内容！","记事本",JOptionPane.WARNING_MESSAGE);

}
private void delete()
{
myarea.replaceSelection("");
}

}

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