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  • 创建模式之单例模式

    懒汉模式:

    /**
     * @author yuyang
     * @DATE 2019/1/7 0007-8:59
     */
    public class Singleton {
        private final static Singleton INSTANCE=null;
        private Singleton(){}
        public static synchronized Singleton getInstance(){
            if (INSTANCE==null){
                return  new Singleton();
            }else {
                return INSTANCE;
            }
        }
    }

    饿汉模式

    public class Singleton {
        private final static Singleton INSTANCE = new Singleton();
        private Singleton(){}
        public static Singleton getInstance(){
            return INSTANCE;
        }
    }

    静态内部类

    public class Singleton {
        private Singleton() {}
        private static class SingletonInstance {
            private static final Singleton INSTANCE = new Singleton();
        }
        public static Singleton getInstance() {
            return SingletonInstance.INSTANCE;
        }
    }
    同步方法

    同步代码块

    双重检查

    public class Singleton {
        private static volatile Singleton singleton;
        private Singleton() {}
        public static Singleton getInstance() {
            if (singleton == null) {
                synchronized (Singleton.class) {
                    if (singleton == null) {
                        singleton = new Singleton();
                    }
                }
            }
            return singleton;
        }
    }
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  • 原文地址:https://www.cnblogs.com/yuyangcoder/p/10231383.html
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