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使用ObjectInputStream的readObject()方法如何判断读取到多个对象的结尾

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

使用ObjectInputStream的readObject()方法如何判断读取到多个对象的结尾

 

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

import cn.com.mybolg.bean.Person;

/*
 * 若文件中有若干个Object对象,你用ObjectInputStream中的readObject()去读,何时判读到结尾?
 * 方法之一:(常用的方法)将若干个对象(数量不定)都装入一个容器中(如:ArrayList之类),
 * 然后将容器这一个对象写入就行了。读取时,只要读取一个对象(即容器对象)就行了。
 * 
 * 方法之二:(若不想用容器),则由于数量不定,正是用EOFException来判断结束。
 * 代码结构如下:(无论是readInt()读int,还是readObject()读对象) 
 * try{
 *  while(true) {
 *   Object o=ois.radObject(); 
 *   处理已读出的对象o; 
 *   }
 *  }
 *  catch(EOFException e){ 
 *  //已从流中读完。 
 *  } 
 *  finallly {
 * 流的关闭。 }
 */

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();
        }
    }

}

 

 以下是自己的试验:

往文件里存多个对象也没问题,调用writeObject()一直往里写即可,readObject()一次返回一个对象,再readObject()一次返回第二个对象,自动在每个对象后面做标记。并且同一个文件中可以依次存入不同类的对象。先存入一个Person对象,再存入一个Demo对象,再存个Haha对象都可以。按顺序读就行了。

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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;
    }

}

 

使用ObjectInputStream的readObject()方法如何判断读取到多个对象的结尾