单例模式
在一个jvm中有且仅有一个对象
(1)内部静态类实现
class Singleton{
/*构造方法私有 防止实例化*/
private Singleton(){};
public static Singleton getInstance(){
SingletonFactory.instance;
}
public static class SingletonFactory{
private static Singleton instance = new Singleton();
}
private Object readObject(){
return getInstance;
}
}
(2)synchronized
class Singleton{
private Singleton instance = null;
/*构造方法私有 防止实例化*/
private Singleton(){};
public Singleton getInstance(){
if(instance==null)syncInst();
return instance;
}
private static synchronized void syncInst(){
if(singleton==null){
singleton = new Singleton1();
}
}
}