Не понимаю, почему метод readResolve должен иметь тип Object. Мне представляется логичным, что должен быть тип Singleton.
package com.javarush.task.task20.task2008;
import java.io.*;
/*
Как сериализовать Singleton?
*/
public class Solution implements Serializable {
public static void main(String[] args) throws IOException, ClassNotFoundException {
Singleton instance = Singleton.getInstance();
ByteArrayOutputStream byteArrayOutputStream = serializeSingletonInstance(instance);
Singleton singleton = deserializeSingletonInstance(byteArrayOutputStream);
Singleton singleton1 = deserializeSingletonInstance(byteArrayOutputStream);
System.out.println("Проверка ourInstance : " + singleton.getInstance());
System.out.println("Проверка ourInstance : " + singleton1.getInstance());
System.out.println("=========================================================");
System.out.println("Проверка singleton : " + singleton);
System.out.println("Проверка singleton1 : " + singleton1);
}
public static ByteArrayOutputStream serializeSingletonInstance(Singleton instance) throws IOException {
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(byteArrayOutputStream);
oos.writeObject(instance);
oos.close();
return byteArrayOutputStream;
}
public static Singleton deserializeSingletonInstance(ByteArrayOutputStream byteArrayOutputStream) throws IOException, ClassNotFoundException {
ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
ObjectInputStream ois = new ObjectInputStream(byteArrayInputStream);
Singleton singleton = (Singleton) ois.readObject();
ois.close();
return singleton;
}
public static class Singleton implements Serializable {
private static Singleton ourInstance;
public static Singleton getInstance() {
if (ourInstance == null) {
ourInstance = new Singleton();
}
return ourInstance;
}
private Singleton() {
}
private Singleton readResolve(){
return ourInstance;
}
}
}