保证一个类仅有一个实例,并提供一个访问它的全局访问点.
public class SingletonTest
{
public static void main(String[] args)
{
Singleton singleton = Singleton.getInstance();
Singleton singleton2 = Singleton.getInstance();
System.out.println(singleton == singleton2);
}
}
class Singleton
{
private static Singleton singleton = new Singleton();
private Singleton()
{
}
public static Singleton getInstance()
{
return singleton;
}
}
输出 true
通过一个简单的例子来了解单例模式.