常見設計模式之【單例模式】

遇到類似的問題：生產編號的產生，售票系統等資料需要同步，馬上想到單例模式....

例子代碼：

package Singleton;/** *@Description: 單例模式 *@author Potter    *@date 2012-8-14 下午10:08:16 *@version V1.0    */public class App {public static void main(String[] args) {NumDevice g=NumDevice.getInstance();//Greedy2 g=Greedy2.INSTANCE;System.out.println(g.next());show();}public static void show(){NumDevice g=NumDevice.getInstance();//NumDevice2 g=NumDevice2.INSTANCE;System.out.println(g.next());}}

方法一：用類實現：

package Singleton;/** *@Description: 單例類 *@author Potter    *@date 2012-8-14 下午10:01:45 *@version V1.0    */public class NumDevice {private final static NumDevice me=new NumDevice();private NumDevice(){}public static NumDevice getInstance(){return me;}private int count;public int next(){return count++;}}

方法二：用枚舉類

package Singleton;/** *@Description: 單例類 *@author Potter    *@date 2012-8-14 下午10:01:45 *@version V1.0    */public enum NumDevice2 {INSTANCE;private int count;public int next(){return count++;}}