有关java.security.AccessControlException的问题
写了一个程序
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
public class FileGUIBak extends JApplet implements ActionListener
{
private JLabel prompt = new JLabel( "prompt ");
private JTextField nameInput = new JTextField(20);
private JButton read = new JButton( "ReadFile ");
private JButton write = new JButton( "WriteFile ");
private JTextArea display = new JTextArea(10,40);
private JPanel control = new JPanel();
private JPanel displayPanel = new JPanel();
private void writeTextFile(JTextArea dis, String fileName){
try{
FileWriter outStream = new FileWriter(fileName);
outStream.write(dis.getText());
outStream.close();
}
catch(IOException e){
display.setText( "IOERROR: " +e.getMessage() + "\n ");
e.printStackTrace();
}
}
private void readTextFile(JTextArea dis, String fileName){
try{
BufferedReader inStream = new BufferedReader(new FileReader(fileName));
String line = inStream.readLine();
while(line != null){
dis.append(line + "\n ");
line = inStream.readLine();
}
inStream.close();
}
catch(FileNotFoundException e){
display.setText( "IOERROR: File NOT Found: " + fileName + "\n ");
e.printStackTrace();
}
catch(IOException e){
display.setText( "IOERROR: " + e.getMessage() + "\n ");
e.printStackTrace();
}
}
private void initControl(){
read.addActionListener(this);
write.addActionListener(this);
control.setBorder(BorderFactory.createTitledBorder( "Control "));
control.setLayout(new FlowLayout());
control.add(prompt);
control.add(nameInput);
control.add(read);
control.add(write);
}
private void initDisplay(){
displayPanel.setBorder(BorderFactory.createTitledBorder( "Display "));
displayPanel.setLayout(new FlowLayout());
display.setLineWrap(true);
displayPanel.add(new JScrollPane (display));
}
public void init(){
initControl();
initDisplay();
getContentPane().setLayout(new BorderLayout());
getContentPane().add(control, "North ");
getContentPane().add(displayPanel, "Center ");
getContentPane().setSize(500,300);
}
public void actionPerformed(ActionEvent e){
if(e.getSource() == read){
readTextFile(display,nameInput.getText());
}
else{
writeTextFile(display,nameInput.getText());
}
}
};
和FileGUIBak.htm
<html>
<body>
<table align= "center ">
<td>
<applet code= "FileGUIBak.class " width= "500 " height= "300 ">
</applet>
</td>
</table>
</body>
</html>
用appletview时, read可用而write不可用报错如下
java.security.AccessControlException:access denied
可是一样的程序写成JFrame的就可以
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
public class TextIO extends JFrame implements ActionListener
{
private JTextArea display = new JTextArea();
private JButton read = new JButton( "Read From File ");
private JButton write = new JButton( "Write to File ");
private JTextField nameField = new JTextField(20);
private JLabel prompt = new JLabel( "Filename : ", JLabel.RIGHT);
private JPanel commands = new JPanel();
public TextIO(){
super( "TextIO Demo ");
read.addActionListener(this);
write.addActionListener(this);
commands.setLayout(new GridLayout(2,2,1,1));
commands.add(prompt);
commands.add(nameField);
commands.add(read);
commands.add(write);
display.setLineWrap(true);
this.getContentPane().setLayout(new BorderLayout());
this.getContentPane().add( "North ", commands);
this.getContentPane().add( new JScrollPane(display));
this.getContentPane().add( "Center ",display);
}
private void readTextFile(JTextArea display, String fileName){
try{
BufferedReader inStream = new BufferedReader(new FileReader(fileName));
String line = inStream.readLine();
while(line != null){
display.append(line + "\n ");
line = inStream.readLine();
}
inStream.close();
}
catch(FileNotFoundException e){
display.setText( "IOERROR: FILE NOT FOUND: " + fileName + "\n ");
e.printStackTrace();
}
catch(IOException e){
display.setText( "IOERROR: " + e.getMessage() + "\n ");
e.printStackTrace();
}
}
private void writeTextFile(JTextArea display,String fileName){
try{
FileWriter outStream = new FileWriter(fileName);
outStream.write(display.getText());
outStream.close();
}
catch(IOException e){
display.setText( "IOERROR: " +e.getMessage() + "\n ");
e.printStackTrace();
}
}
public void actionPerformed(ActionEvent e){
String fileName = nameField.getText();
if(e.getSource() == read){
display.setText( " ");
readTextFile(display, fileName);
}
else
writeTextFile(display, fileName);
}
public static void main(String args [ ]){
TextIO tio = new TextIO();
tio.setSize(400,200);
tio.setVisible(true);
tio.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
}
}
不知为什么，请高手指教
------解决方案--------------------
顶！
