Java单例模式(Singleton)的实现
单例模式的三个特点：
1，该类只有一个实例
2，该类自行创建该实例(在该类内部创建自身的实例对象)
3，向整个系统公开这个实例接口

实现方法一：立即加载

public class Singleton{private static Singleton singleton = null;public static Singleton getInstanse(){if (singleton == null){singleton = new Singleton();}return singleton;}private Singleton() {}public static void main(String[] args){Singleton t = Singleton.getInstanse();Singleton t2 = Singleton.getInstanse();System.out.println(t == t2);}}