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设计模式——简单工厂模式

1.适用范围：工厂类负责创建的对象较少的场景，且客户端只需要传入工厂类的参数，对如何创建对象不关心。
2.缺点：工厂类的职责过重，不易于扩展过于复杂的产品结构。

3.实例：

//动物接口
public interface Animal {public void play();
}

//猫类
public class Cat implements Animal {@Overridepublic void play() {System.out.println("遛猫");}
}

//狗类
public class Dog implements Animal {@Overridepublic void play() {System.out.println("遛狗");}
}

//动物简单工厂类
public class AnimalFactory {public Animal create1(String name){if("cat".equals(name)){return new Cat();}else if ("dog".equals(name)){return new Dog();}else{return  null;}}//create1:若需要增加动物，则要改动create方法,不符合开闭原则，因此采用反射机制// 采用反射机制public Animal create(String className){try {if (!(null == className || "".equals(className))){//需要强转类型return (Animal) Class.forName(className).newInstance();}} catch (Exception e) {e.printStackTrace();}return null;}//方法参数为字符串，同时需要类型的强制转换//对反射代码的优化public Animal create(Class<? extends Animal> sonClass) {try {if (null != sonClass) {return sonClass.newInstance();}} catch (Exception e) {e.printStackTrace();}return null;}
}

import org.junit.Test;//测试类
public class TestSimpleFactory {@Testpublic void test1(){AnimalFactory animalFactory = new AnimalFactory();Animal animal = animalFactory.create1("cat");animal.play();}//反射代码的测试@Testpublic void test2(){AnimalFactory animalFactory = new AnimalFactory();Animal animal = animalFactory.create("com.sqx.simpleFactory.Dog");animal.play();}//反射代码优化的测试@Testpublic void test3(){AnimalFactory animalFactory = new AnimalFactory();Animal animal = animalFactory.create(Dog.class);animal.play();}
}