- /*
- 单例设计模式。
- */
- //饿汉式。
- /*
- class Single
- {
- private static final Single s = new Single();
- private Single(){}
- public static Single getInstance()
- {
- return s;
- }
- }
- */
- //懒汉式
- class Single
- {
- private static Single s = null;
- private Single(){}
- public static Single getInstance()
- {
- if(s==null)
- {
- synchronized(Single.class)
- {
- if(s==null)
-
- s = new Single();
- }
- }
- return s;
- }
- }
- class SingleDemo
- {
- public static void main(String[] args)
- {
- System.out.println("Hello World!");
- }
- }
复制代码
听说这里经常考试,今天复习到这里了,分享一下,大家也注意下。 |