Singleton Pattern

最新推荐文章于 2025-02-11 14:12:50 发布

原创最新推荐文章于 2025-02-11 14:12:50 发布 · 311 阅读

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本文详细介绍了单例模式的三种实现方式：早期初始化、懒加载和双重检查锁定优化方案。通过对比不同模式的特点，帮助读者理解如何根据实际需求选择合适的单例模式实现。

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Singleton Pattern:

1. Early mode

public class President{
    private static President instance = new President();
    private President() {}
    
    public static President getInstance() {
        return instance;
    }
}

2. Lazy mode:

public class President{
    private static President instance;
    private President() {}
    
    public static synchronized President getInstance() {
        if(instace == null){
            instance = new President();
        }
        return instance;
    }
}

3. Optimize solution: (double checked locking)

public class President{
    private static volatile President instance;
    private President() {}
    
    public static President getInstance() {
        if(instance == null) {
            synchronized(President.class){
                if(instance == null){
                    instance = new President();
                }
            }
        }
         return instance;
    }
}