try {
FileInputStream fis = new FileInputStream("test");
MessageDigest md = MessageDigest.getInstance("SHA");
DigestInputStream dis = new DigestInputStream(fis, md);
ObjectInputStream ois = new ObjectInputStream(dis);
Object o = ois.readObject();
if (!(o instanceof String)) {
System.out.println("Unexpected data in file");
System.exit(-1);
}
String data = (String) o;
System.out.println("Got message " + data);
dis.on(false);
o = ois.readObject();
if (!(o instanceof byte[])) {
System.out.println("Unexpected data in file");
System.exit(-1);
}
byte origDigest[] = (byte []) o;
if (MessageDigest.isEqual(md.digest(), origDigest))
System.out.println("Message is valid");
else System.out.println("Message was corrupted");
} catch (Exception e) {
System.out.println(e);
}
