IO 包中的ObjectInputStream和ObjectOutputStream

import java.io.*;

class ObjectStreamDemo 
{
	public static void main(String[] args) throws Exception
	{
		//writeObj();
		readObj();
	}
	public static void readObj()throws Exception
	{
		ObjectInputStream ois = new ObjectInputStream(new FileInputStream("obj.txt"));

		Person p = (Person)ois.readObject();

		System.out.println(p);
		ois.close();
	}

	public static void writeObj()throws IOException
	{
		ObjectOutputStream oos = 
			new ObjectOutputStream(new FileOutputStream("obj.txt"));

		oos.writeObject(new Person("lisi0",399,"kr"));

		oos.close();
	}
}

import java.io.*;
class Person implements Serializable //继承Serializable（没有方法 称为标记接口 为类提供一个UID号 用于区分） 
{
	
	public static final long serialVersionUID = 42L;//用此方法固定一个UID 即使改变此类也可以继续读取

	private String name;//序列化堆内存中的内容
	transient int age;//不是静态想不被序列化 用transient修饰
	static String country = "cn";//静态存在于方法区中 不会被序列化
	Person(String name,int age,String country)
	{
		this.name = name;
		this.age = age;
		this.country = country;
	}
	public String toString()
	{
		return name+":"+age+":"+country;
	}
}