JAVA 单例模式

//懒汉式
public class Singleton {
	private static Singleton singleton;
	private Singleton(){
		
	}
	public static Singleton getSingleton(){
		if(singleton==null)
			singleton = new Singleton();
		return singleton;
	}
	public static void main(String[] args) {
		Singleton s1 = Singleton.getSingleton();
		Singleton s2 = Singleton.getSingleton();
		System.out.println(s1==s2);
		
		Singleton s3 = new Singleton();
		Singleton s4 = new Singleton();
		System.out.println(s3==s4);
	}
}

//饿汉式
public class Singleton{
	private final static Singleton sigleton = new Singleton();
	private Singleton(){
		
	}
	public static Singleton getSingleton(){
		return sigleton;
	}
	public static void main(String[] args) {
		Singleton s1 = new Singleton();
		Singleton s2 = new Singleton();
		System.out.println(s1==s2);
		
		Singleton s3 = Singleton.getSingleton();
		Singleton s4 = Singleton.getSingleton();
		System.out.println(s3==s4);
	}
}