使用ObjectInputStream的readObject()方法如何判斷讀取到多個對象的結尾

摘自http://blog.csdn.net/fjdingsd/article/details/46765803

使用ObjectInputStream的readObject()方法如何判斷讀取到多個對象的結尾

 

import java.io.EOFException;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.ObjectInputStream;

import cn.com.mybolg.bean.Person;

/*
 * 若文件中有若干個Object對象，你用ObjectInputStream中的readObject()去讀，何時判讀到結尾？
 * 方法之一：（常用的方法）將若干個對象（數量不定）都裝入一個容器中（如：ArrayList之類），
 * 然后將容器這一個對象寫入就行了。讀取時，只要讀取一個對象（即容器對象）就行了。
 * 
 * 方法之二：（若不想用容器），則由於數量不定，正是用EOFException來判斷結束。
 * 代碼結構如下：(無論是readInt()讀int，還是readObject()讀對象) 
 * try{
 *  while(true) {
 *   Object o=ois.radObject(); 
 *   處理已讀出的對象o; 
 *   }
 *  }
 *  catch(EOFException e){ 
 *  //已從流中讀完。 
 *  } 
 *  finallly {
 * 流的關閉。 }
 */

public class ObjectInputStreamDemo {

    public static void main(String[] args) throws IOException, ClassNotFoundException {
        
        FileInputStream fis = new FileInputStream("F:\\person.object");
        ObjectInputStream osi = new ObjectInputStream(fis);
        
        try {
            while(true) {
                Person p = (Person) osi.readObject();
                System.out.println(p.getName()+":"+p.getAge());
            }
        }
        catch(EOFException e) {
            
        }
        finally {
            osi.close();
        }
    }

}

 

 以下是自己的試驗：

往文件里存多個對象也沒問題，調用writeObject()一直往里寫即可，readObject()一次返回一個對象，再readObject()一次返回第二個對象，自動在每個對象后面做標記。並且同一個文件中可以依次存入不同類的對象。先存入一個Person對象，再存入一個Demo對象，再存個Haha對象都可以。按順序讀就行了。

package packa;

import java.io.*;

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

    private static void writeObj()throws Exception
    {
        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("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"));
        System.out.println(ois.readObject());
        System.out.println(ois.readObject());
        System.out.println(ois.readObject());

        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;
    }

}