我编写的这段代码为什么两个按钮只出现了一个。。

Question

import javax.swing.*;
import java.awt.event.*;
import java.io.*;
class fileoperator implements ActionListener{
JFrame jf=new JFrame("fileoperator");
JTextArea ta=new JTextArea(10,10);
fileoperator(){
JPanel p=new JPanel();
JButton open=new JButton("读文件");
JButton save=new JButton("写文件");
jf.add(ta);jf.add(open);jf.add(save);jf.add(p,"South");
open.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JFileChooser jfc=new JFileChooser();
jfc.showOpenDialog(jf);
File file=jfc.getSelectedFile();
try {
FileInputStream fis=new FileInputStream(file);
InputStreamReader isr=new InputStreamReader(fis);
BufferedReader br=new BufferedReader(isr);
String s;
ta.setText("");
while((s=br.readLine())!=null)
ta.append(s+"\n");
br.close();
}catch(Exception ee) {
System.out.println("文件不存在！");
}
}

     });
     save.addActionListener(this);
     jf.setBounds(200, 200, 200,200);
     jf.setVisible(true);
 }
 public void actionPerformed(ActionEvent e) {
     JFileChooser jfc=new JFileChooser();
     jfc.showSaveDialog(jf);
     File file=jfc.getSelectedFile();
     try {
         FileOutputStream fos=new FileOutputStream(file);
         OutputStreamWriter osw=new OutputStreamWriter(fos);
         BufferedWriter bw=new BufferedWriter(osw);
         String s;
         bw.write(ta.getText());
         bw.close();

     }catch(Exception ee){
         System.out.println("没有存储空间！");

     }
 }

}
class FiletoUnicode{
public static void main(String []ppp) {
new fileoperator();
}
}

Answer 1

可能是布局问题吧，你试下把save按钮的渲染注释掉，看看open按钮有没有出来。如果出来了说明是布局问题，在同一位置上，open按钮被save按钮盖住了