设计模式之工厂方法模式
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2024-01-05 17:14:28
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- 结构
抽象工厂Factory + 具体工厂ConcreteFactory + 抽象产品Product + 具体产品ConcreteProduct - 适用环境
客户端不知道它所需要的对象的类,抽象工厂类通过其子类来指定创建哪个对象。 - 实现
public interface Factory {
public Product createProduct();
}
public class ProductAFactory implements Factory {
@Override
public Product createProduct() {
System.out.println("产品A初始化");
Product product = new ProductA();
return product;
}
}
public class ProductBFactory implements Factory {
@Override
public Product createProduct() {
System.out.println("产品B初始化");
Product product = new ProductB();
return product;
}
}
public interface Product {
public void productDetaile();
}
public class ProductA implements Product{
@Override
public void productDetaile() {
System.out.println("产品A详情");
}
}
public class ProductB implements Product {
@Override
public void productDetaile() {
System.out.println("产品B详情");
}
}
public class Client {
public static void main(String[] args) {
Factory factory;
Product product;
factory = (Factory)XMLUtils.getBean();
product = factory.createProduct();
product.productDetaile();
}
}
控制台输出:
产品B初始化
产品B详情
//该方法用于从XML配置文件中提取类的类名,并返回实例对象
public static Object getBean(){
try {
DocumentBuilderFactory dFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = dFactory.newDocumentBuilder();
Document doc;
doc = builder.parse(new File("resources//createPattern//factoryMethod//config.xml"));
NodeList nodeList = doc.getElementsByTagName("className");
Node firstChild = nodeList.item(0).getFirstChild();
String className = firstChild.getNodeValue().trim();
Class c = Class.forName(className);
Object object = c.newInstance();
return object;
}catch (Exception e){
e.printStackTrace();
return null;
}
}
<?xml version="1.0" encoding="UTF-8"?>
<config>
<className>createPattern.factoryMethod.ProductBFactory</className>
</config>
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