如何使用Applet写入文件？

解决方法

下面的例子演示了如何使文本区域使用浏览器写TextArea()使标签和使用File()构造函数创建文件写入到文件。

import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.applet.Applet;
import java.net.*;

public class WriteFile extends Applet{
   Button write = new Button("WriteToFile");
   Label label1 = new Label("Enter the file name:");
   TextField text = new TextField(20);
   Label label2 = new Label("Write your text:");
   TextArea area = new TextArea(10,20);
   public void init(){
      add(label1);
      label1.setBackground(Color.lightGray);
      add(text);
      add(label2);
      label2.setBackground(Color.lightGray);
      add(area);
      add(write,BorderLayout.CENTER);
      write.addActionListener(new ActionListener (){
        public void actionPerformed(ActionEvent e){
           new WriteText();
        }
     }
   );
}
public class WriteText {
   WriteText(){
      try {
         String str = text.getText();
         if(str.equals("")){
            JOptionPane.showMessageDialog(null,
            "Please enter the file name!");
            text.requestFocus();
         }
         else{
            File f = new File(str);
            if(f.exists()){
               BufferedWriter out = new 
               BufferedWriter(new FileWriter(f,true));
               if(area.getText().equals("")){
                  JOptionPane.showMessageDialog
                  (null,"Please enter your text!");
                  area.requestFocus();
               }
               else{
                  out.write(area.getText());
                  if(f.canWrite()){
                     JOptionPane.showMessageDialog(null,
                     "Text is written in "+str);
                     text.setText("");
                     area.setText("");
                     text.requestFocus();
                  }
                  else{
                     JOptionPane.showMessageDialog(null,
                     "Text isn't written in "+str);
                  }
                  out.close();
                  }
               }
               else{
                  JOptionPane.showMessageDialog
                  (null,"File not found!");
                  text.setText("");
                  text.requestFocus();
               }
            }
         }
         catch(Exception x){
            x.printStackTrace();
         }
      }
   }
}

结果

上面的代码示例将产生一个java的web浏览器，结果如下。

View in Browser. 

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