序列化心得

package SerializeDemo;

import java.io.*;

public class Fruit  implements Serializable {
	int size = 42;

	Fruit(String s) {
		System.out.println("fruit...");
	}
	Fruit() {
		System.out.println("fruit...");
	}

}

package SerializeDemo;

import java.io.*;

public class Apple extends Fruit{
	
	int as = 3;
	
	private transient String s = "I'm not serializable..." ;
	
	public Apple() {
//		super("aa");
		System.out.println("the as is :" + as);
	}
	
	public void writeObject(ObjectOutputStream os) {
		try {
			os.defaultWriteObject();
			os.writeObject(s);
		} catch (IOException e) {
			e.printStackTrace();
		}
		
		System.out.println("invoke the writeObject...");
		
	}
	

	public void readObject(ObjectInputStream os) {
		System.out.println("invoke the readObject...");
		try {
			os.defaultReadObject();
//			s = (String)os.readObject();
		} catch (IOException e) {
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}
	
	public Apple readApple(FileInputStream is) {
		Apple a = null;
		try {
			ObjectInputStream ois = new ObjectInputStream(is);			
			a = (Apple)ois.readObject();			
			ois.close();			
		}
		catch(Exception e) {
			e.printStackTrace();
		}
		return a;
	}
	
	public void saveApple(FileOutputStream os,Object obj) {
		try {
			ObjectOutputStream oos = new ObjectOutputStream(os);
			oos.writeObject(obj);
			oos.close();
		}
		catch(Exception e) {
			e.printStackTrace();
		}
	}
	
	public static void main(String[] args) {
		try {
			FileOutputStream fos = new FileOutputStream("Apple.txt");
			FileInputStream fis = new FileInputStream("Apple.txt");
			
			Apple a = new Apple();
			a.size = 20;  //super original 42
			a.as = 20;
			
			a.saveApple(fos, a);
			Apple b = a.readApple(fis);
//			System.out.println("b.size is:"+b.size+"\tb.as is:"+b.as);
			System.out.println("b.size is:"+b.size+"\tb.as is:"+b.as+"\tb.food is:"+b.s);
			
		}
		catch(Exception e) {
			e.printStackTrace();
		}	
	}
}