Java IO.pdf - Nguyen Dang Binh

public class SealedPoint {
}
public static void main(String[] args) {
}
String filename = "point.des";
Point tdp = new Point(32, 45);
try {
FileOutputStream fout = new FileOutputStream(filename);
ObjectOutputStream oout = new ObjectOutputStream(fout);
Java I/O
// Create a key.
byte[] desKeyData = {(byte) 0x90, (byte) 0x67, (byte) 0x3E,
(byte) 0xE6, (byte) 0x42, (byte) 0x15, (byte) 0x7A, (byte) 0xA3 };
DESKeySpec desKeySpec = new DESKeySpec(desKeyData);
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
SecretKey desKey = keyFactory.generateSecret(desKeySpec);
// Use Data Encryption Standard.
Cipher des = Cipher.getInstance("DES/ECB/PKCS5Padding");
des.init(Cipher.ENCRYPT_MODE, desKey);
SealedObject so = new SealedObject(tdp, des);
oout.writeObject(so);
oout.close();
}
catch (IOException e) { System.err.println(e); }
catch (GeneralSecurityException e) { System.err.println(e); }
Reading a sealed object from an object input stream is easy. You read it exactly as you read
any other object from an object input stream. For example:
FileInputStream fin = new FileInputStream(filename);
ObjectInputStream oin = new ObjectInputStream(fin);
SealedObject so = (SealedObject) oin.readObject();
Once you've read the object, unsealing it to retrieve the original object is straightforward,
provided you know the key. There are three getObject() methods that return the original
object:
public final Object getObject(Key key) throws IOException,
ClassNotFoundException, NoSuchAlgorithmException, InvalidKeyException
public final Object getObject(Cipher c) throws IOException,
ClassNotFoundException, IllegalBlockSizeException, BadPaddingException
public final Object getObject(Key key, String provider) throws IOException,
ClassNotFoundException, NoSuchAlgorithmException,
NoSuchProviderException,
InvalidKeyException
The first variant is the most useful, since it only requires the key. It does not require you to
create and initialize a Cipher object. You will in general need to know the algorithm used in
order to know what kind of key to create, but that information is available from the
getAlgorithm() method:
public final String getAlgorithm()
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