题解 | #创建单例对象#

public class Main {

    public static void main(String[] args) {
        Singleton s1 = Singleton.getInstance();
        Singleton s2 = Singleton.getInstance();
        System.out.println(s1 == s2);
    }

}

class Singleton {

    private static Singleton instance;

    private Singleton() {

    }

    //write your code here......
    public static Singleton getInstance(){
        if(instance==null)
            instance=new Singleton();//单例需要将属性和构造方法私有化，并且判断是否已经new了对象，如果是则返回对象，否则new一个对象再返回
        return instance;
    }

}