懒汉式单例

package www.bittech.java;
class Singleton{
    private static Singleton singleton;
    private Singleton(){}
    public static Singleton getInstance(){
        if(singleton == null){
            singleton = new Singleton();
        }
        return singleton;
    }
}
public class Test {
    public static void main(String[] args) {
        //通过Singleton类的外部就可以调用方法取得一个对象
        Singleton singleton1 = Singleton.getInstance();
        Singleton singleton2 = Singleton.getInstance();
        System.out.println(singleton1==singleton2);
    }
}