參考兩篇博客：

http://blog.csdn.net/moreevan/article/details/6697777

http://blog.csdn.net/moreevan/article/details/6698529

針對(duì)第二篇博客，看了下面的評(píng)論，發(fā)現(xiàn)子類輸出的書號(hào)其實(shí)是父類的，書名是自己先添加的成員變量，我自己在實(shí)驗(yàn)的時(shí)候，發(fā)現(xiàn)子類NewBook中使用父類Book的變量部分，輸出的都沒有值：基本類型的系統(tǒng)默認(rèn)值是0，非基礎(chǔ)類型例如字符串系統(tǒng)默認(rèn)是null

然后，當(dāng)把父類Book實(shí)現(xiàn)了序列化接口時(shí)，這是才能全部輸出子類的變量值：

并且第二篇博客里也寫到了，如果在打印對(duì)象的時(shí)候，會(huì)調(diào)用對(duì)象的toString方法，即使我在子類中覆蓋了toString()方法并且沒有調(diào)用父類的toString方法，但是系統(tǒng)依然報(bào)出了第二篇博客中提到的那個(gè)錯(cuò)誤：java.io.InvalidClassException: NewBook; no valid constructor

所以父類中加了個(gè)空的無參構(gòu)造函數(shù)，這樣就可以正常打印出來了，下面是全碼：

1、父類沒有實(shí)現(xiàn)序列化接口：(此時(shí)不可以打印子類的變量值)

importjava.io.Serializable;public classBook {intbook_num;

String book_authour;//構(gòu)造函數(shù)

public Book(intabook_num, String abook_author)

{this.book_num =abook_num;this.book_authour =abook_author;

}publicBook()

{

}//設(shè)置作者名

public voidsetBookAuthor(String abook_author)

{this.book_authour =abook_author;

}//設(shè)置書號(hào)

public void setBookNum(intabook_num)

{this.book_num =abook_num;

}//打印對(duì)象

publicString toString(){return "book_num:"+book_num+"\n"+"book_anthor:"+book_authour;

}

}

2、父類實(shí)現(xiàn)序列化接口：(此時(shí)可以打印子類的變量值)

importjava.io.Serializable;public class Book implementsSerializable {intbook_num;

String book_authour;/*** 實(shí)現(xiàn)序列化接口的時(shí)候一定要分配序列ID*/

private static final long serialVersionUID = 1L;//構(gòu)造函數(shù)

public Book(intabook_num, String abook_author)

{this.book_num =abook_num;this.book_authour =abook_author;

}publicBook(){

}//設(shè)置作者名

public voidsetBookAuthor(String abook_author)

{this.book_authour =abook_author;

}//設(shè)置書號(hào)

public void setBookNum(intabook_num)

{this.book_num =abook_num;

}//打印對(duì)象

publicString toString(){return "book_num:"+book_num+"\n"+"book_anthor:"+book_authour;

}

}

3、子類：

importjava.io.Serializable;public class NewBook extends Book implementsSerializable{privateString book_version;/*** 實(shí)現(xiàn)序列化接口的時(shí)候一定要分配序列ID*/

private static final long serialVersionUID = 1L;public NewBook(intabook_num, String abook_author,String abook_version)

{super(abook_num, abook_author);this.book_version =abook_version;//TODO Auto-generated constructor stub

}

@Overridepublic voidsetBookAuthor(String abook_author)

{//TODO Auto-generated method stub

super.setBookAuthor(abook_author);

}

@Overridepublic void setBookNum(intabook_num)

{//TODO Auto-generated method stub

super.setBookNum(abook_num);

}public voidsetBookVersion(String abook_version)

{

book_version=abook_version;

}

@OverridepublicString toString()

{//TODO Auto-generated method stub

return "new_book_num:"+book_num+"new_book_anthor:"+book_authour+"new_book_version"+book_version;

}

}

4、主函數(shù)：

importjava.io.EOFException;importjava.io.File;importjava.io.FileInputStream;importjava.io.FileNotFoundException;importjava.io.FileOutputStream;importjava.io.IOException;importjava.io.ObjectInputStream;importjava.io.ObjectOutput;importjava.io.ObjectOutputStream;public classBookSerializable {public static voidmain(String args[])

{/** Java里的main方法里不能直接調(diào)用非靜態(tài)的對(duì)象，要么調(diào)用靜態(tài)變量，要么調(diào)用在方法內(nèi)部實(shí)例化的非靜態(tài)局部變量*/NewBook new_book1=new NewBook(1,"呼嘯山莊","1.0");

NewBook new_book2=new NewBook(2,"紅與黑","2.0");/** 將對(duì)象序列化到文件中*/

try{

File fil= new File("C://JavaFile//red_bean.txt");if(!fil.exists())

{

fil.createNewFile();

}

FileOutputStream fil_input= newFileOutputStream(fil);

ObjectOutputStream obj_output= newObjectOutputStream(fil_input);

obj_output.writeObject(new_book1);

obj_output.reset();

new_book1.setBookVersion("3.0");

obj_output.writeObject(new_book1);

obj_output.reset();

new_book1.setBookVersion("4.0");

obj_output.writeObject(new_book1);

obj_output.writeObject(new_book2);

obj_output.writeObject(null);//寫入結(jié)束標(biāo)志方便讀取(非常重要，如果不寫入，在讀取的時(shí)候無法定位讀取結(jié)束)；

obj_output.close();//關(guān)閉對(duì)象輸出流

fil_input.close();//關(guān)閉文件輸出流

} catch(FileNotFoundException e) {//TODO Auto-generated catch block

e.printStackTrace();

}catch(IOException e) {//TODO Auto-generated catch block

e.printStackTrace();

}/** 將對(duì)象從文件中讀出來*/ObjectInputStream obj_input;try{

FileInputStream fil_input= new FileInputStream("C://JavaFile//red_bean.txt");

obj_input= newObjectInputStream(fil_input);

Object boj;while((boj = obj_input.readObject())!=null)//循環(huán)讀取對(duì)象流

{

NewBook new_bookReadTemp=(NewBook)boj;

System.out.println(new_bookReadTemp);/** 讀出的時(shí)候按照寫入的順序讀取*/

/*NewBook new_bookRead1 = (NewBook)obj_input.readObject();

NewBook new_bookRead2 = (NewBook)obj_input.readObject();

NewBook new_bookRead3 = (NewBook)obj_input.readObject();

NewBook new_bookRead4 = (NewBook)obj_input.readObject();

//NewBook new_bookRead5 = (NewBook)obj_input.readObject();

System.out.println(new_bookRead1);

System.out.println(new_bookRead2);

System.out.println(new_bookRead3);

System.out.println(new_bookRead4);

//System.out.println(new_bookRead5);*/}

obj_input.close();

fil_input.close();

}catch(EOFException e){

e.printStackTrace();

}catch(FileNotFoundException e) {//TODO Auto-generated catch block

e.printStackTrace();

}catch(ClassNotFoundException e) {//TODO Auto-generated catch block

e.printStackTrace();

}catch(IOException e) {//TODO Auto-generated catch block

e.printStackTrace();

}

}

}

自己動(dòng)手敲了一遍代碼的感受：

確實(shí)應(yīng)該多多動(dòng)手呀！編慣了Android，感覺養(yǎng)成了很不好的語法習(xí)慣，main()是個(gè)靜態(tài)方法，我還在main方法外面定義了了非靜態(tài)對(duì)象，在main方法里用，顯然不行啊，調(diào)用非靜態(tài)方法，然后在非靜態(tài)方法里使用非靜態(tài)變量，或者直接在main方法里定義非靜態(tài)局部變量并使用，Java里沒有全局變量的概念，要共享數(shù)據(jù)就專門定義一個(gè)share類， 里面全是靜態(tài)的變量方法。不要把安卓的onCreat和main混在一起。main里的變量定義和使用：http://blog.csdn.net/zi_jun/article/details/7553132

其他的Java序列化較好博客：

http://blog.csdn.net/wangzhiqing3/article/details/8392803

Java文件操作：

http://www.cnblogs.com/springcsc/archive/2009/12/03/1616367.html

http://blog.csdn.net/smartcat86/article/details/4085739/

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