工厂模式-单例模式

单例模式

class Singleton{private static Singleton singleton = null; public static Singleton getInstance(){if(null == singleton){singleton = new Singleton();} return singleton;} public String otherOperation(){ //方法实现}} Client: String str = Singleton.getInstance().otherOperation(); 

多线程时使用double-check模式确保线程安全：

class Singleton{private static Singleton singleton = null; public static Singleton getInstance(){ if(null == singleton) sychronized (Singleton.class){ if(null == singleton){singleton = new Singleton();}}} return singleton; }}