黑马程序员_打开文件存储文件

最新推荐文章于 2023-07-20 15:30:30 发布

a87848180

最新推荐文章于 2023-07-20 15:30:30 发布

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CC 4.0 BY-SA版权

文章标签：存储 string exception null file menu

本文链接：https://blog.youkuaiyun.com/a87848180/article/details/7647434

本文提供了一个Java Swing GUI应用程序的示例代码，演示了如何实现文件的打开和保存功能。通过使用菜单项来触发文件对话框，用户可以加载和保存文本文件的内容。

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class practice27

{
private Frame f;
private File fe;
private MenuBar mb;
private Menu m;
private MenuItem mload,msave,mclose;
private TextArea ta;
practice27()
{
ini();
}
public void ini()
{
f=new Frame();
ta=new TextArea();
mb=new MenuBar();
m=new Menu("文件");
mload=new MenuItem("打开");
msave=new MenuItem("保存");
mclose=new MenuItem("关闭");
f.setBounds(200,100,500,400);
f.setLayout(new FlowLayout());
f.add(ta);
f.setMenuBar(mb);
mb.add(m);
m.add(mload);
m.add(msave);
m.add(mclose);
method();
f.setVisible(true);
}
public void method()
{
f.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);
}});
mclose.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
System.exit(0);
}
});
mload.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
try{
FileDialog fdg=new FileDialog(f,"",FileDialog.LOAD);
fdg.setVisible(true);
String dirpath=fdg.getDirectory();
String filepath=fdg.getFile();

if(dirpath==null||filepath==null)
return;
ta.setText("");
fe=new File(dirpath+filepath);
String line;
BufferedReader bis=new BufferedReader(new InputStreamReader(new FileInputStream(fe)));
while((line=bis.readLine())!=null)
{
//String sb=new String(b,0,len);
ta.append(line+"\r\n");
System.out.println(ta.getText());
}
}
catch (Exception ex)
{
throw new RuntimeException("。。。。");
}

}

}
);
msave.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
try
{
String textstr=ta.getText();
if(fe==null)
{
FileDialog fdg=new FileDialog(f,"",FileDialog.SAVE);
fdg.setVisible(true);
String dirpath=fdg.getDirectory();
String filepath=fdg.getFile();
if(dirpath==null||filepath==null)
return;
else{
fe=new File(dirpath,filepath);}}
PrintStream ps=new PrintStream(new FileOutputStream(fe),true);
ps.println(textstr);
}
catch (Exception ex)
{
throw new RuntimeException("；；；；");
}
}
});

}
public static void main(String[] args)
{
new practice27();
}

}
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