单例模式

如题

Java中单例模式的使用有很多方法

1.懒汉式，饿汉式，等等

用到哪个整理哪个

懒汉式

饿汉式

双检查

private static CameraPhotographPresenter sInstance;

private CameraPhotographPresenter(){
}

public static CameraPhotographPresenter getInstance() {
    if(sInstance==null){
        synchronized (CameraPhotographPresenter.class){
            if(sInstance==null){
                sInstance = new CameraPhotographPresenter();
            }
        }
    }
    return sInstance;
}