我需要一些帮助。
在显示“您的代码已生成”的部分后,继续获取Null Pointer Exception。当我运行我的代码时,我无法弄清楚原因。
在将asHex类添加到同一个包中的新java文件之前,它工作正常,但现在即使删除了asHex也无法工作。
任何人都可以帮助我吗?
代码:
public class myDesCbc2 {
public static void main(String[] args) throws FileNotFoundException, UnsupportedEncodingException, IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidAlgorithmParameterException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
JFrame frame = null;
JFileChooser fChoose = new JFileChooser(System.getProperty("user.home"));
int returnVal = fChoose.showOpenDialog(frame);
File myFile = fChoose.getSelectedFile();
FileInputStream fis = new FileInputStream(myFile);
BufferedReader stream = new BufferedReader(new InputStreamReader(fis, "ISO-8859-1"));
String file;
while ((file = stream.readLine()) != null) {
JOptionPane.showOptionDialog(
null, "Generating a 56-bit DES key...", "Processing...", JOptionPane.DEFAULT_OPTION, JOptionPane.INFORMATION_MESSAGE, null, new Object[]{}, null);
}
// Create an 8-byte initialization vector
SecureRandom sr = new SecureRandom();
byte[] iv = new byte[8];
sr.nextBytes(iv);
IvParameterSpec IV = new IvParameterSpec(iv);
// Create a 56-bit DES key
KeyGenerator kg = KeyGenerator.getInstance("DES");
// Initialize with keysize
kg.init(56);
Key mykey = kg.generateKey();
JOptionPane.showOptionDialog(
null, "Your key has been generated!", "Processing...", JOptionPane.DEFAULT_OPTION, JOptionPane.INFORMATION_MESSAGE, null, new Object[]{}, null);
// Create a cipher object and use the generated key to initialize it
Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, mykey, IV);
byte[] plaintext = file.getBytes("UTF8");
// Encrypt the text
byte[] ciphertext = cipher.doFinal(plaintext);
JOptionPane.showMessageDialog(
null, "Your ciphertext is" + asHex(ciphertext), "Done!", JOptionPane.PLAIN_MESSAGE);
}
}
asHex代码:
public class asHex {
public static String asHex (byte buf[]) {
StringBuffer strbuf = new StringBuffer(buf.length * 2);
int i;
for (i = 0; i < buf.length; i++) {
if (((int) buf[i] & 0xff) < 0x10)
strbuf.append("0");
strbuf.append(Long.toString((int) buf[i] & 0xff, 16));
}
return strbuf.toString();
}
}
答案 0 :(得分:1)
将while循环后的代码放在while循环中,这应解决问题。否则,当执行while循环后的代码导致错误时,该文件为空。