public static Singleton GetInstance()
{
if (null == instance)
{
instance = new Singleton();
}
return instance;
}
public static Singleton GetInstance()
{
if (instance == null)
{
lock (syncRoot)
{
if (instance == null)
{
instance = new Singleton();
}
}
}
return instance;
}
/// <summary>
/// 定义公有方法提供一个全局访问点,同时你也可以定义公有属性来提供全局访问点
/// </summary>
/// <returns></returns>
public static Singleton GetInstance()
{
// 当第一个线程运行到这里时，此时会对locker对象 "加锁"，
// 当第二个线程运行该方法时，首先检测到locker对象为"加锁"状态，该线程就会挂起等待第一个线程解锁
// lock语句运行完之后（即线程运行完之后）会对该对象"解锁"
// 双重锁定只需要一句判断就可以了
if (uniqueInstance == null)
{
lock (locker)
{
// 如果类的实例不存在则创建，否则直接返回
if (uniqueInstance == null)
{
uniqueInstance = new Singleton();
}
}
}
return uniqueInstance;
}
public static Singleton GetInstance()
{
//if (instance == null)
//{
// instance = new Singleton();
// Console.WriteLine(i++);
//}
//return instance;
if (instance == null)
{
lock (obj) //通过Lock关键字实现同步
{
if (instance == null)
{
instance = new Singleton();
Console.WriteLine(i++);
}
}
}
return(instance);
}
public static Singleton GetInstance()
{
if (instance == null)
instance = new Singleton();
return instance;
}
static void Main(string[] args)
{
Singleton.Instance();
Console.ReadKey();
}
