静态工厂：工厂初始化之前，工厂中的类已经被实例化放在工厂容器中

public class StaticFactory {
    public static void main(String[] args) {
        Object bean = StaticFactory.getBean();
    }
    public static Object getBean(){
        return new Object();
    }
}

实例工厂：工厂在构造方法初始化时,会将类进行实例化放在工厂中

class InstanceFactory {
    public static void main(String[] args) {
        InstanceFactory factory = new InstanceFactory();
        Object bean = factory.getBean();    
    }
    public  Object getBean(){
        return new Object();
    }
}