package com.model.newb.danli;
/**
* 使用双重校验锁
* */
public class Singleton {
private Singleton() {}
private static volatile Singleton instance;
public static Singleton getInstance(){
if(instance == null){
synchronized(Singleton.class){ // 锁的是类
if(instance == null ){
instance = new Singleton();
}
}
}
return instance;
}
}