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Java反射与工厂设计模式

程序员文章站 2022-03-09 20:29:44
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如:传统工厂类

interface IFruit{
	void eat();
}
class Apple implements IFruit{
	public void eat() {
		System.out.println("吃苹果");
	}
}
class Orange implements IFruit{
	public void eat() {
		System.out.println("吃橘子");
	}
}
class Factory{
	private Factory() {}
	public static IFruit getInstance(String name) {
		if("apple".equals(name)) {
			return new Apple();
		}if("orange".equals(name)) {
			return new Orange();
		}
		return null;
	}
}
public class Test{
	public static void main(String[] args) {
		IFruit fruit1 = Factory.getInstance("apple");
		fruit1.eat();
		IFruit fruit2 = Factory.getInstance("orange");
		fruit2.eat();
	}
}
特点:每增加一个接口子类就需要修改工厂类。

如:利用反射实现工厂类

interface IFruit{
	void eat();
}
class Apple implements IFruit{
	public void eat() {
		System.out.println("吃苹果");
	}
}
class Orange implements IFruit{
	public void eat() {
		System.out.println("吃橘子");
	}
}
class Factory{
	private Factory() {}
	public static IFruit getInstance(String name) throws InstantiationException, IllegalAccessException, ClassNotFoundException {
		IFruit fruit = (IFruit) Class.forName(name).newInstance();
		return fruit;
	}
}
public class Test{
	public static void main(String[] args) throws InstantiationException, IllegalAccessException, ClassNotFoundException {
		IFruit fruit = Factory.getInstance("test4.Apple");
		fruit.eat();
	}
}
特点:无论增加多少接口子类都不用修改工厂类。