java简单的记事本

本文是关于java记事本的一个简单的代码实现问题，由于是初学者，所以记事本的界面有点简单，布局有点简陋，所需代码如下：

import java.awt.BorderLayout;
import java.awt.FileDialog;
import java.awt.Font;
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.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;


import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.border.TitledBorder;




public class NotePad extends JFrame {
private static final long serialVersionUID = -5355432125621015300L;
private String url = null;//文件路径
private String str=null;//复制或剪切 的字符串
private StringSelection stringSelection=null;
private Clipboard clipboard=new Clipboard(str);
private Transferable   transferable=null;
private DataFlavor   flavor=null;
public NotePad() {
init();
}


private void init() {
setTitle("记事本");
setSize(480, 620);
setContentPane(createContentPane());//添加主面板
}

/*创建主面板*/
private JPanel createContentPane() {
JPanel pane = new JPanel(new BorderLayout());


pane.add(BorderLayout.NORTH, createChocePane());//添加菜单栏
pane.add(createAreaPane());//添加文本编辑区域


return pane;
}


/*创建菜单栏，以及实现功能*/
private JPanel createChocePane() {
JPanel pane = new JPanel();
JMenuBar menuBar1 = new JMenuBar();
JMenu menu = new JMenu("文件");
menuBar1.add(menu);
JMenuItem menuIt1 = new JMenuItem("新建");
JMenuItem menuIt2 = new JMenuItem("打开");
JMenuItem menuIt3 = new JMenuItem("保存");
JMenuItem menuIt4 = new JMenuItem("另存为");
menu.add(menuIt1);
menu.add(menuIt2);
menu.add(menuIt3);
menu.add(menuIt4);


JMenuBar menuBar2 = new JMenuBar();
JMenu menu2 = new JMenu("编辑");
menuBar2.add(menu2);
JMenuItem menuIt5 = new JMenuItem("复制");
JMenuItem menuIt6 = new JMenuItem("剪切");
JMenuItem menuIt7 = new JMenuItem("粘帖");
menu2.add(menuIt5);
menu2.add(menuIt6);
menu2.add(menuIt7);


JMenuBar menuBar3 = new JMenuBar();
JMenu menu3 = new JMenu("帮助");
menuBar3.add(menu3);
JMenuItem menuIt8 = new JMenuItem("关于记事本");
menu3.add(menuIt8);


pane.add(menuBar1);
pane.add(menuBar2);
pane.add(menuBar3);


menuIt1.addActionListener(new ActionListener() {


public void actionPerformed(ActionEvent e) {
testArea.setText(null);
}
});


menuIt2.addActionListener(new ActionListener() {


public void actionPerformed(ActionEvent arg0) {


final FileDialog fd = new FileDialog(new JFrame(), "查找文件",
FileDialog.LOAD);
fd.setVisible(true);


if (fd.getDirectory() != null && fd.getFile() != null) {
testArea.setText(null);
url = fd.getDirectory() + fd.getFile();
try {
BufferedReader in = new BufferedReader(new FileReader(
url));
for (int i = 0;; i++) {
testArea.append(in.readLine());
if (in.read() == -1) {
break;
} else
continue;
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}


});


menuIt3.addActionListener(new ActionListener() {


public void actionPerformed(ActionEvent e) {
if (url==null) {
url="E:\\记事本.txt";
}


File f = new File(url);
BufferedWriter out = null;
try {
out = new BufferedWriter(new FileWriter(url));
f.createNewFile();
out.append(testArea.getText());
out.flush();


} catch (IOException e1) {
e1.printStackTrace();
} finally {
try {
out.close();
} catch (IOException e1) {
e1.printStackTrace();
}
}

}
});


menuIt4.addActionListener(new ActionListener() {


public void actionPerformed(ActionEvent arg0) {
FileDialog fd = new FileDialog(new JFrame(), "保存文本",
FileDialog.SAVE);
fd.setVisible(true);
if (url!=null) {
File f = new File(url);
BufferedWriter out = null;
try {
f.createNewFile();
out = new BufferedWriter(new FileWriter(url));
out.append(testArea.getText());
out.flush();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
});

menuIt5.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {
str=testArea.getSelectedText();
stringSelection=new   StringSelection(str); 
clipboard.setContents(stringSelection, null);
}
});

menuIt6.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent arg0) {
str=testArea.getSelectedText();
stringSelection=new   StringSelection(str); 
clipboard.setContents(stringSelection, null);
 int   start=testArea.getSelectionStart(); 
 int   end=testArea.getSelectionEnd(); 
 testArea.replaceRange( null,start,end); 


}
});

menuIt7.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {
transferable=clipboard.getContents(this);
flavor=DataFlavor.stringFlavor;
if (transferable.isDataFlavorSupported(flavor)) {
int   start=testArea.getSelectionStart(); 
int   end=testArea.getSelectionEnd(); 
testArea.replaceRange( null,start,end); 
int   pos=testArea.getCaretPosition(); 
try {
str=(String)transferable.getTransferData(flavor);
testArea.insert(str, pos);
} catch (UnsupportedFlavorException e1) {
e1.printStackTrace();
} catch (IOException e1) {
e1.printStackTrace();
} 






}
}
});

menuIt8.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {
JOptionPane.showMessageDialog(null,"详情请加：QQ1150580768");
}
});


return pane;
}


JTextArea testArea;


private JScrollPane createAreaPane() {
JScrollPane pane = new JScrollPane();
pane.setBorder(new TitledBorder("文本编辑区"));
testArea = new JTextArea();
testArea.setFont(new Font("宋体", Font.BOLD, 13));
testArea.setLineWrap(true);
pane.getViewport().add(testArea);
return pane;
}


public static void main(String[] args) {
NotePad td = new  NotePad();
td.setVisible(true);
}


}

运行结果如下：