package com.phone.week5.day2;
//这种写法叫饿汉式
//懒汉式
public class Singleton {
private Singleton(){}
private static Singleton single=null;
//Class cls = Singleton.class
public static Singleton getInstance(){
//--->a
if(single==null){
synchronized(Singleton.class){
if(single==null){
single = new Singleton();
}
}
}
return single;
}
}