单例模式根据实例化对象时机的不同分为两种:一种是饿汉式单例
,一种是懒汉式单例
。
私有的构造方法
指向自己实例的私有静态引用
以自己实例为返回值的静态的公有的方法
饿汉式单例
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public class Singleton { private static Singleton singleton = new Singleton(); private Singleton(){} public static Singleton getInstance(){ return singleton; } } |
懒汉式单例
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public class Singleton { private static Singleton singleton; private Singleton(){} public static synchronized Singleton getInstance(){ if (singleton== null ){ singleton = new Singleton(); } return singleton; } }<br> |
工厂方法模式代码
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interface IProduct { public void productMethod(); } class Product implements IProduct { public void productMethod() { System.out.println( "产品" ); } } interface IFactory { public IProduct createProduct(); } class Factory implements IFactory { public IProduct createProduct() { return new Product(); } } public class Client { public static void main(String[] args) { IFactory factory = new Factory(); IProduct prodect = factory.createProduct(); prodect.productMethod(); } } |
抽象工厂模式代码
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interface IProduct1 { public void show(); } interface IProduct2 { public void show(); } class Product1 implements IProduct1 { public void show() { System.out.println( "这是1型产品" ); } } class Product2 implements IProduct2 { public void show() { System.out.println( "这是2型产品" ); } } interface IFactory { public IProduct1 createProduct1(); public IProduct2 createProduct2(); } class Factory implements IFactory{ public IProduct1 createProduct1() { return new Product1(); } public IProduct2 createProduct2() { return new Product2(); } } public class Client { public static void main(String[] args){ IFactory factory = new Factory(); factory.createProduct1().show(); factory.createProduct2().show(); } } |
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原文链接:http://blog.csdn.net/wuxiao5570/article/details/70154159