视频里的简易文本文档代码问题 - 黑马程序员技术交流社区

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.awt.MenuBar.*;
class A
{
private Frame f;
private MenuBar bar; //菜单栏
private Menu fileMenu,subMenu,TryMenu; //菜单
private MenuItem closeItem,subItem,openItem,saveItem; //菜单项
private TextArea ta;
private File file;
private FileDialog openDia,saveDia;
A()
{
init();
}
public void init()
{
f=new Frame("my window");
f.setBounds(300,100,500,600);
//f.setLayout(new FlowLayout());去掉布局默认为边界布局，此时可以让布局大小随着TextArea的变化而变化
ta=new TextArea();
bar=new MenuBar();
fileMenu=new Menu("文件");
subMenu=new Menu("子菜单");
openItem=new MenuItem("打开");
saveItem=new MenuItem("保存");
closeItem=new MenuItem("退出");
subItem=new MenuItem("子条目");
TryMenu=new Menu("Try");
fileMenu.add(openItem);
fileMenu.add(saveItem);
fileMenu.add(closeItem); bar.add(TryMenu);
bar.add(fileMenu); //菜单栏添加菜单
f.setMenuBar(bar);
f.setVisible(true);
f.add(ta);
fileMenu.add(subMenu);//菜单添加菜单
subMenu.add(subItem);//菜单添加菜单项
openDia= new FileDialog(f,"我要打开",FileDialog.LOAD);
saveDia= new FileDialog(f,"我要保存",FileDialog.SAVE);
myEvent();
}
public void myEvent()
{
closeItem.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
System.exit(0);
}
});
f.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});
openItem.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
openDia.setVisible(true);
String dirPath=openDia.getDirectory();
String FileName=openDia.getFile();
if(dirPath==null || FileName==null)
return ;
file=new File(dirPath,FileName);
try
{
ta.setText("");
BufferedReader bufr=new BufferedReader(new FileReader(file));
String line=null;
while((line=bufr.readLine())!=null)
{
ta.append(line+"\r\n");
}
bufr.close();
}
catch(IOException e1)
{
throw new RuntimeException("读取文件失败");
}
}
});
saveItem.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e2)
{
if(file==null)
saveDia.setVisible(true);
String dirPath=saveDia.getDirectory();
String fileName=saveDia.getFile();
if(dirPath==null || fileName==null)
return ;
file=new File(dirPath,fileName);
try
{
BufferedWriter bufw=new BufferedWriter(new FileWriter(file));
String text=ta.getText();
bufw.write(text);
bufw.close();
}
catch(IOException e3)
{
throw new RuntimeException("写入数据失败");
}
}
});
}
public static void main(String[] args)
{
new A();
}
}

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