【Java】Java单例模式

private static SingleDemo me = null;

public static SingleDemo creatDemo()

public static SingleDemo creatDemo(){
   if(me == null) me = new SingleDemo();
   return me;
}

public class SingleDemo {
	private static SingleDemo me = null;
	public int count=0;
	private SingleDemo() {
		count++;
	}
	//思考：单例模式为何需要返回
	public static SingleDemo creatDemo() {
		if(me == null) me=new SingleDemo();//单例模式重点，保证所有对象创建的是同一个实例
		return me;
	}

}

public class SingleTest {
	public static void main(String[] args) {
//		SingleDemo s1 = new SingleDemo();
		SingleDemo s1 = SingleDemo.creatDemo();

		SingleDemo s2 = SingleDemo.creatDemo();
		System.out.println(s1.count);
		s1.count++;
		System.out.println(s2.count);
		System.out.println(s1==s2);//true
	}
}