The ObjectOutputStream
serializes objects, arrays, and other values to a stream. The
writeObject( ) method serializes an object or
array, and various other methods write primitive data values to the
stream. Note that only objects that implement the
Serializable or Externalizable
interface can be serialized.
A class that wants to customize the way instances are serialized
should declare a private
writeObject(ObjectOutputStream) method. This method is invoked when an object
is being serialized and can use several additional methods of
ObjectOutputStream. defaultWriteObject(
) performs the same serialization that would happen if no
writeObject( ) method existed. An object can call
this method to serialize itself and then use other methods of
ObjectOutputStream to write additional data to the
serialization stream. The class must define a matching
readObject( ) method to read that additional data, of
course. When working with multiple versions or implementations of a
class, you may have to serialize a set of fields that do not
precisely match the fields of your class. In this case, give your
class a static field named
serialPersistentFields whose value is an array of
ObjectStreamField objects that describe the fields
to be serialized. In your writeObject( ) method,
call putFields( ) to obtain an
ObjectOutputStream.PutField object. Store field
names and values into this object, and then call
writeFields( ) to write them out to the
serialization stream. See ObjectStreamField and
ObjectOutputStream.PutField for further details.
The remaining methods of ObjectOutputStream are
miscellaneous stream-manipulation methods and protected methods for
use by subclasses that want to customize its serialization behavior.
public class ObjectOutputStream extends OutputStream implements ObjectOutput,
ObjectStreamConstants {
// Public Constructors
public ObjectOutputStream(OutputStream out) throws IOException;
// Protected Constructors
1.2 protected ObjectOutputStream( ) throws IOException, SecurityException;
// Nested Types
1.2 public abstract static class PutField;
// Public Instance Methods
public void defaultWriteObject( ) throws IOException;
1.2 public ObjectOutputStream.PutField putFields( ) throws IOException;
public void reset( ) throws IOException;
1.2 public void useProtocolVersion(int version) throws IOException;
1.2 public void writeFields( ) throws IOException;
1.4 public void writeUnshared(Object obj) throws IOException;
// Methods Implementing DataOutput
public void writeBoolean(boolean val) throws IOException;
public void writeByte(int val) throws IOException;
public void writeBytes(String str) throws IOException;
public void writeChar(int val) throws IOException;
public void writeChars(String str) throws IOException;
public void writeDouble(double val) throws IOException;
public void writeFloat(float val) throws IOException;
public void writeInt(int val) throws IOException;
public void writeLong(long val) throws IOException;
public void writeShort(int val) throws IOException;
public void writeUTF(String str) throws IOException;
// Methods Implementing ObjectOutput
public void close( ) throws IOException;
public void flush( ) throws IOException;
public void write(int val) throws IOException;
public void write(byte[ ] buf) throws IOException;
public void write(byte[ ] buf, int off, int len) throws IOException;
public final void writeObject(Object obj) throws IOException;
// Protected Instance Methods
protected void annotateClass(Class<?> cl) throws IOException; empty
1.3 protected void annotateProxyClass(Class<?> cl) throws IOException; empty
protected void drain( ) throws IOException;
protected boolean enableReplaceObject(boolean enable) throws SecurityException;
protected Object replaceObject(Object obj) throws IOException;
1.3 protected void writeClassDescriptor(ObjectStreamClass desc) throws IOException;
1.2 protected void writeObjectOverride(Object obj) throws IOException; empty
protected void writeStreamHeader( ) throws IOException;
}
