使用Java中的FileChooser進行選擇後加密文件

Question

對於我的新項目，我嘗試在gui中選擇文檔後對其進行編碼。我的程序包含兩個部分，一個選擇文件，另一個對其進行編碼。所以在選擇一個文件之後，應該調用加密方法，但它並不真正起作用，因爲路徑似乎沒有被採用。

public class frame1 { 

    String filepath; 

    public static void main(String[] args) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IOException { 
     JFrame.setDefaultLookAndFeelDecorated(true); 
     JDialog.setDefaultLookAndFeelDecorated(true); 
     JFrame frame = new JFrame("Test"); 
     frame.getContentPane().setLayout(new FlowLayout()); 
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     JButton button = new JButton("Encrypt"); 
     button.addActionListener(new ActionListener() { 
      public void actionPerformed(ActionEvent ae) { 
      JFileChooser fileChooser = new JFileChooser(); 
      FileNameExtensionFilter filter = new FileNameExtensionFilter("TEXT FILES","txt", "text"); 
      fileChooser.setFileFilter(filter); 
      int returnValue = fileChooser.showOpenDialog(null); 
      if (returnValue == JFileChooser.APPROVE_OPTION) { 
       File selectedFile = fileChooser.getSelectedFile(); 
        System.out.println(selectedFile.getAbsolutePath()); 
        String filepath = selectedFile.getAbsolutePath(); 

      } 
     frame.getContentPane().add(button); 
     frame.pack(); 
     frame.setVisible(true); 

     public void encrypt() throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IOException { 
     KeyGenerator keygenerator = KeyGenerator.getInstance("AES"); 
     SecretKey myDesKey = keygenerator.generateKey(); 
     Cipher desalgCipher; 
     desalgCipher = Cipher.getInstance("AES"); 
     desalgCipher.init(Cipher.ENCRYPT_MODE, myDesKey); 

     Path path = Paths.get(filepath); 
     try(InputStream is = Files.newInputStream(path);  
     CipherInputStream cipherIS = new CipherInputStream(is, desalgCipher); 
     BufferedReader reader = new BufferedReader(new InputStreamReader(cipherIS));){ 
      String line; 
      while((line = reader.readLine()) != null){ 
       System.out.println(line);    
      } 
     } 
     }   
} 

Answer 1

一個簡單的改變就可以使你的程序是從選擇器返回的文件傳遞給你的encrypt()方法。例如：

import javax.crypto.*; 
import javax.swing.*; 
import javax.swing.filechooser.FileNameExtensionFilter; 
import java.awt.*; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.io.*; 
import java.nio.file.Files; 
import java.nio.file.Paths; 
import java.security.InvalidKeyException; 
import java.security.NoSuchAlgorithmException; 

public class App { 
    public static void main(String[] args) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IOException { 
     JFrame.setDefaultLookAndFeelDecorated(true); 
     JDialog.setDefaultLookAndFeelDecorated(true); 

     JFrame frame = new JFrame("Test"); 
     frame.getContentPane().setLayout(new FlowLayout()); 
     frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); 

     JButton button = new JButton("Encrypt"); 
     button.addActionListener(new ActionListener() { 
      public void actionPerformed(ActionEvent ae) { 
       JFileChooser fileChooser = new JFileChooser(); 
       FileNameExtensionFilter filter = new FileNameExtensionFilter("TEXT FILES", "txt", "text"); 
       fileChooser.setFileFilter(filter); 
       int returnValue = fileChooser.showOpenDialog(null); 
       if (returnValue == JFileChooser.APPROVE_OPTION) { 
        File selectedFile = fileChooser.getSelectedFile(); 
        System.out.println(selectedFile.getAbsolutePath()); 
        String filepath = selectedFile.getAbsolutePath(); 
        try { 
         encrypt(filepath); 
        } catch (Exception e) { 
         e.printStackTrace(); 
        } 
       } 
      } 

      public void encrypt(String path) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IOException { 
       KeyGenerator keygenerator = KeyGenerator.getInstance("AES"); 
       SecretKey myDesKey = keygenerator.generateKey(); 
       Cipher desalgCipher; 
       desalgCipher = Cipher.getInstance("AES"); 
       desalgCipher.init(Cipher.ENCRYPT_MODE, myDesKey); 

       try (InputStream is = Files.newInputStream(Paths.get(path)); 
        CipherInputStream cipherIS = new CipherInputStream(is, desalgCipher); 
        BufferedReader reader = new BufferedReader(new InputStreamReader(cipherIS));) { 
        String line; 
        while ((line = reader.readLine()) != null) { 
         System.out.println(line); 
        } 
       } 
      } 
     }); 

     frame.getContentPane().add(button); 
     frame.setSize(300, 400); 
     frame.setVisible(true); 
    } 
}