/**
 * 餓漢式
 */
class Hungry private constructor() {
    companion object {
        private val instance = Hungry()//類加載的時(shí)候就實(shí)例化，并且創(chuàng)建單例對象

        fun getInstance(): Hungry {
            return instance
        }

    }

}

/**
 * 懶漢式
 */
class Lazy private constructor() {
    companion object {
        private var instance: Lazy? = null

        fun getInstance(): Lazy {
            if (instance == null) {
                synchronized(Lazy::class.java) {
                    if (instance == null) {
                        instance = Lazy()
                    }
                }
            }
            return instance!!
        }
    }
}