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直播软件开发，单例设计模式很简单吗？
单例设计模式，相信是大家接触设计模式时的入门设计模式，它理解起来比较简单，当然实现起来也很简单，但是别看不上这简单的东西，简单的事情重复做将不再简单，再复杂的事情拆分开来也是由很多简单的事情的集合。接下来来过一遍三种经典的单例模式。
1、构造方法私有化；
2、实例化的变量引用私有化；
3、获取实例的方法共有。
public class DCLSingleton implements Serializable {private static final long serialVersionUID = 6242241249985894658L;/*** volatile ：内存中可见 和 防止指令重排* 这里主要作用是防止指令重排*/private volatile static DCLSingleton instance;private DCLSingleton() {}public static DCLSingleton getInstance() {if (instance == null) {synchronized (DCLSingleton.class) {if (instance == null) {instance = new DCLSingleton();}}}return instance;}public void singletonFunction() {System.out.println("DCLSingleton test.");}
}
public class StaticSingleton implements Serializable {private static final long serialVersionUID = 5537012394799626447L;private static class SingletonHolder {private static final StaticSingleton INSTANCE = new StaticSingleton();}private StaticSingleton(){}public static final StaticSingleton getInstance() {return SingletonHolder.INSTANCE;}public void singletonFunction() {System.out.println("StaticSingleton test.");}
}
public enum SingletonEnum {/*** 实例*/INSTANCE;/*** 方法*/public void singletonFunction() {System.out.println("SingletonEnum test.");}
}
以单例性和安全性 2 个方向对以上 3 种单例模式进行测试，看哪种比较适合
public class TestSerializable {public static void main(String[] args) throws IOException, ClassNotFoundException {System.out.println("----------------双重否定单例模式测试开始-----------------------------");DCLSingleton instance_1 = DCLSingleton.getInstance();ByteArrayOutputStream byteArrayOutputStream_1 = new ByteArrayOutputStream();new ObjectOutputStream(byteArrayOutputStream_1).writeObject(instance_1);ObjectInputStream objectInputStream_1 = new ObjectInputStream(new ByteArrayInputStream(byteArrayOutputStream_1.toByteArray()));DCLSingleton singleton_1 = (DCLSingleton) objectInputStream_1.readObject();//com.songo.singletonpattern.service.SingletonPattern1@27c170f0System.out.println(instance_1);//com.songo.singletonpattern.service.SingletonPattern1@3d494fbfSystem.out.println(singleton_1);//DCLSingleton test.singleton_1.singletonFunction();//序列化和反序列化后是否相同:falseSystem.out.println("序列化和反序列化后是否相同:" + (instance_1 == singleton_1));System.out.println("----------------双重否定单例模式测试结束-----------------------------");System.out.println("----------------静态内部类单例模式测试开始---------------------------");StaticSingleton instance_2 = StaticSingleton.getInstance();ByteArrayOutputStream byteArrayOutputStream_2 = new ByteArrayOutputStream();new ObjectOutputStream(byteArrayOutputStream_2).writeObject(instance_2);ObjectInputStream objectInputStream_2 = new ObjectInputStream(new ByteArrayInputStream(byteArrayOutputStream_2.toByteArray()));StaticSingleton singleton_2 = (StaticSingleton) objectInputStream_2.readObject();//com.songo.singletonpattern.service.StaticSingleton@7cd84586System.out.println(instance_2);//com.songo.singletonpattern.service.StaticSingleton@30dae81System.out.println(singleton_2);//StaticSingleton test.singleton_2.singletonFunction();//序列化和反序列化后是否相同:falseSystem.out.println("序列化和反序列化后是否相同:" + (instance_2==singleton_2));System.out.println("----------------静态内部类单例模式测试结束---------------------------");System.out.println("----------------枚举单例模式测试结束---------------------------------");SingletonEnum instance_3 = SingletonEnum.INSTANCE;ByteArrayOutputStream byteArrayOutputStream_3 = new ByteArrayOutputStream();new ObjectOutputStream(byteArrayOutputStream_3).writeObject(instance_3);ObjectInputStream objectInputStream_3