单例设计模式总结

//单例模板//饿汉式//Single类一进内存就已经创建好了对象，开发时常使用class Single {private Single() {}private static Single s = new Single();public static Single getInstance() {return s;}}// 懒汉式//Single2类进内存对象还没有存在，只有调用了getInstance方法时才创建对象（延时加载）class Single2 {private Single2() {}private static Single2 s = null;public static Single2 getInstance() {if (s == null) {s = new Single2();}return s;}}public class SingleModel {public static void main(String[] args) {Single s1 = Single.getInstance();}}