OCJP认证-3期（PX017） 面向对象程序设计-IO处理.doc

真题分析

面向对象程序设计

I/O 处理

(1)序列化及解(反)序列化(serialization and deserialization)

import java.io.*;

class Brad implements Serializable {

Brad(){

System.out.println("Brad");

}

class B extends A {

public B(){

System.out.println("B");

}

}

class C extends B implements Serializable {

private Brad brad = new Brad();

public C(){

System.out.println("C");

}

oos.close();

fos.close();

System.out.println("------------------------");

FileInputStream fis = new FileInputStream("oo.tmp");

ObjectInputStream ois = new ObjectInputStream(fis);

C cc = (C)ois.readObject();

ois.close();

fis.close();

}catch (Exception ee){System.out.println("Exception");}

}

public static void main ( String[] args ) {

Forest f = new Forest () ;

try {

FileOutputStream fs = new FileOutputStream ("Forest.Ser") ;

ObjectOutputStream os = new ObjectOutputStream (fs) ;

os.writeObject (f) ;

os.close () ;

} catch (Exception ex) { ex.printStackTrace () ; }

}

}

C. An instance of Forest is serialized.

解析：

� 有编译失败的答案选项, 当然要先检查基本语法.

� Forest 类别宣告 implements Serializable, 而该类别中的对象成员 Tree, 是必须也

可以被串行化, 然而在 Tree 类别并未 implements Serializable.

� 因此会在执行时期, 在执行 os.writeObject (f) ; 时丢出一个

� 里面的成员也是可串行化的，Tree 类继承 Serializable；

(3)Given the following Java code:

1.import java.io.* ;

2.public class Foo implements Serializable {

9.}

10.

11.private void readObject ( ObjectInputStream s )

12.throws IOException, ClassNotFoundException {

13.

14.// insert code here

15.

16.}

17.}

Which code, inserted ay line 14, will allow this to correctly serialized and desterilize?