externalexam.java

Java程序设计实用教程源代码 本书源代码按章分别放置在不同的文件夹中,所有程序均在JDK1.6环境下编译运行正常,除了第13章需要建立ODBC数据源之外,其他程序只要有Java运行环境即可直接运行

import java.io.*;
import java.util.*;
class Serial implements Externalizable{
  String name = "张飞";
  int age = 20;
  public Serial(){
    System.out.println("default constructor");
  }
  public Serial(String name,int age){
    this.name = name;
    this.age = age;
    System.out.println("Not default constructor");
  }
  public void writeExternal(ObjectOutput out)throws IOException{
    System.out.println("run writeExternal");
    Date date=new Date();
    out.writeObject(date);
    out.writeObject(name); 
    out.writeInt(age);
    System.out.println("date in stream is "+date);
  }
  public void readExternal(ObjectInput in)throws IOException,ClassNotFoundException{
    System.out.println("run readExternal");
    Date date=(Date)in.readObject();
    name=(String)in.readObject();
    age=in.readInt();
    System.out.println("date in stream is "+date);
  }
  public String toString() {
    return "name = " + name + ", age = " + age;
  }
}
public class ExternalExam {
  public static void main(String[] args) throws Exception{
    ObjectOutputStream out=new ObjectOutputStream(
                    new FileOutputStream("hero.dat"));
    Serial scrObj=new Serial("令狐冲",18);
    System.out.println("将以下对象序列化");
    System.out.println(scrObj);
    out.writeObject(scrObj);
    out.close();
    System.out.println("开始从文件中恢复对象");
    ObjectInputStream in=new ObjectInputStream(
                    new FileInputStream("hero.dat"));
    Serial sObj=(Serial)in.readObject();
    in.close();
    System.out.println("恢复得到的对象");
    System.out.println(scrObj);
  }
}