package top.qaqaq.java.P437;

/**
 * 使用同步机制将单例模式中的懒汉式改写为线程安全的
 *
 * @author RichieZhang
 * @create 2022-10-21 下午 1:38
 */
public class BankTest {
}

class Bank {

    private Bank() {

    }

    private static Bank instance = null;

    public static Bank getInstance() {
        //方式一：效率稍差
//        synchronized (Bank.class) {
//            if (instance == null) {
//
//                instance = new Bank();
//            }
//        }
//        return instance;
//    }
        //方式二：效率更高
        if (instance == null) {

            synchronized (Bank.class) {
                if (instance == null) {

                    instance = new Bank();
                }
            }
        }
        return instance;
    }

}