public class Singleton {
/**
* 类级的内部类,也就是静态的成员式内部类,该内部类的实例与外部类的实例
* 没有绑定关系,而且只有被调用到才会装载,从而实现了延迟加载
*/
private static class SingletonHolder{
/**
* 静态初始化器,由JVM来保证线程安全
*/
private static Singleton instance = new Singleton();
}
/**
* 私有化构造方法
*/
private Singleton(){
}
public static Singleton getInstance(){
return SingletonHolder.instance;
}
}
public class Singleton {
//private防止外部new
private static Singleton singleton=null;
private Singleton() {} public static Singleton getSingleton() { if(singleton==null) {
singleton = new Singleton(); }
return singleton;
}
}