Question

在思考单例设计模式的同时，我陷入了渴望初始化单例和静态块初始化单例模式之间。让我们说急切初始化单例类代码是 -

public class EagerInitSingleton {

    private static final EagerInitSingleton instance = new EagerInitSingleton();

    //private constructor
    private EagerInitSingleton(){}

    public static EagerInitSingleton getInstance(){
        return instance;
    }
}

和静态块单例类代码如下 -

public class StaticBlockSingleton {

    private static StaticBlockSingleton instance;

    private StaticBlockSingleton(){}

    //static block initialization for exception handling
    static{
        try{
            instance = new StaticBlockSingleton();
        }catch(Exception e){
            throw new RuntimeException("Exception occured in singleton instance");
        }
    }

    public static StaticBlockSingleton getInstance(){
        return instance;
    }
}

请不要谈论懒惰的初始化和线索安全。我想弄清楚静态块单例中的两个静态块如何在这里产生差异。

Answer 1

没有区别。

private static final EagerInitSingleton instance = new EagerInitSingleton();

相当于

private static final EagerInitSingleton instance;

static {
    instance = new EagerInitSingleton();
}

急切初始化singleton vs lazy初始化单例

1 个答案: