ObjectOutputStream 追加写入读取错误

 本篇博客灵感来自http://blog.csdn.net/chenssy/article/details/13170015

 问题描述、问题出现的原因、尝试解决办法，请参见鄙人上一编博客。

上一编文章解决ObjectOutputStream 追加写入读取错误问题的方法是自定义了一个ObjectOutputStream子类，我觉得不如用匿名内部类实现方便，于是自我研究写出以下两种方案。个人更推崇方案二

方案一：

package packa;

import java.io.*;

class ObjectInputOutputStream2
{
    public static void main(String[] args)throws Exception
    {
        writeObj();
        readObj();
    }

    private static void writeObj()throws Exception
    {
        final File f = new File("person.object");
        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("person.object", true))
        {
            protected  void writeStreamHeader()throws IOException
            {
                if (!f.exists() || (f.exists() && 0 == f.length()))
                {
                    super.writeStreamHeader();
                }
            }
        };

        oos.writeObject(new Person("liu", 30, "kr"));
        oos.writeObject(new Person2("liu", "kr", "kr2"));
        oos.writeObject(new Person3(10, 30, 50));

        oos.close();
    }

    private static void readObj()throws Exception
    {
        ObjectInputStream ois = new ObjectInputStream(new FileInputStream("person.object"));

        try
        {
            while(true)
            {
                System.out.println(ois.readObject());    
            }
        }
        catch (Exception e)
        {
            System.out.println(e.toString());
        }

        ois.close();
    }
}

方案二：

package packa;

import java.io.*;

class ObjectInputOutputStream
{
    public static void main(String[] args)throws Exception
    {
        writeObj();
        readObj();
    }

    static ObjectOutputStream  getObjectOutputStreamInstance(final OutputStream os, final File f) throws IOException
    {
        return  new ObjectOutputStream(os)
        {
            protected  void writeStreamHeader()throws IOException
            {
                if (!f.exists() || (f.exists() && 0 == f.length()))
                {
                    super.writeStreamHeader();
                }
            }
        };
    }

    private static void writeObj()throws Exception
    {
        ObjectOutputStream oos = getObjectOutputStreamInstance(new FileOutputStream("person.object", true), new File("person.object"));
        oos.writeObject(new Person("liu", 30, "kr"));
        oos.writeObject(new Person2("liu", "kr", "kr2"));
        oos.writeObject(new Person3(10, 30, 50));

        oos.close();
    }

    private static void readObj()throws Exception
    {
        ObjectInputStream ois = new ObjectInputStream(new FileInputStream("person.object"));

        try
        {
            while(true)
            {
                System.out.println(ois.readObject());    
            }
        }
        catch (Exception e)
        {
            System.out.println(e.toString());
        }

        ois.close();
    }
}

package packa;

import java.io.*;

class Person implements Serializable
{
    public static final long serialVersionUID = 44L;

    String name;
    transient int age;
    static String country = "cn";

    Person(String name, int age, String country)
    {
        this.name = name;
        this.age = age;
        this.country = country;
    }

    public String toString()
    {
        return name + " " + age + " " + country;
    }

}
class Person2 implements Serializable
{
    public static final long serialVersionUID = 45L;

    String name;
    String country;
    String country2;

    Person2(String name, String country, String country2)
    {
        this.name = name;
        this.country = country;
        this.country2 = country2;
    }

    public String toString()
    {
        return name + " " + country + " " + country2;
    }

}
class Person3 implements Serializable
{
    public static final long serialVersionUID = 46L;

    int age;
    int age2;
    int age3;

    Person3(int age, int age2, int age3)
    {
        this.age = age;
        this.age2 = age2;
        this.age3 = age3;
    }

    public String toString()
    {
        return age + " " + age2 + " " + age3;
    }

}