Serializing Objects - Beginning Java - page 545

The ObjectInput and ObjectOutput interfaces extend the DataInput and DataOutput interfaces that
declare methods for reading and writing data of the primitive types and add the methods for reading and
writing objects. The ObjectInputStream class implements ObjectInput and ObjectOutputStream im-
plements ObjectOutput . Both object stream classes implement the ObjectStreamConstants interface,
which defines constants that are used to identify elements of an object in the stream. They both implement
the AutoClosable interface so they can be closed automatically if you create the objects within a try block
with resources.
WRITING AN OBJECT TO A FILE
To write objects to a file, the constructor for the ObjectOutputStream class requires a reference to an Out-
putStream object as an argument, and this object defines the stream that encapsulates the file in which you
intend to store your objects. You can create an ObjectOutputStream object from a channel with the follow-
ing statements:
Path file = Paths.get("MyObjectFile");
// Check out the file path...
// Create the object output stream for the file
try (ObjectOutputStream objectOut =
new ObjectOutputStream(Files.newOutputStream(file))){
// Write to the object output stream...
} catch(IOException e) {
e.printStackTrace();
}
I discussed the static newOutputStream() method that the Files class defines in Chapter 10. Here
you have not specified any open options so the default options assumed are WRITE , CREATE , and
TRUNCATE_EXISTING . The ObjectOutputStream constructor throws an exception of type IOException if
an error occurs while the stream header is being written to the file.