實現serilaizable的對象：
public class MySerializable implements Serializable{
private static final long serialVersionUID = 12345L;
public String Name;
}
//序列化過程
User user = new User();
ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("cache.txt"));
out.writeObject(user);
out.close();
//反序列化過程
User newUser = (User) in.readObject();
ObjectInputStream in = new ObjectInputStream(new FileInputStream("cache.txt"));
in.close();