java 工厂模式的讲解及优缺点的介绍

package scut.designmodel.SimpleFactoryPattern;

//抽象产品类
abstract class Product{
  public abstract void Show();
}

//产品A类
class ProductA extends Product{

  @Override
  public void Show() {
    System.out.println("生产出了产品A");
  }
}

//产品B类
class ProductB extends Product{

  @Override
  public void Show() {
    System.out.println("生产出了产品C");
  }
}

//产品C类
class ProductC extends Product{

  @Override
  public void Show() {
    System.out.println("生产出了产品C");
  }
}

//简单工厂类
class Factory {
  public static Product Manufacture(String ProductName){
    switch (ProductName){
      case "A":
        return new ProductA();

      case "B":
        return new ProductB();

      case "C":
        return new ProductC();

      default:
        return null;

    }
  }
}

//工厂产品生产流程
public class SimpleFactoryPattern {
  public static void main(String[] args){
    Factory mFactory = new Factory();

    //客户要产品A
    try {
      mFactory.Manufacture("A").Show();
    }catch (NullPointerException e){
      System.out.println("没有这一类产品");
    }

    //客户要产品B
    try {
      mFactory.Manufacture("B").Show();
    }catch (NullPointerException e){
      System.out.println("没有这一类产品");
    }

    //客户要产品C
    try {
      mFactory.Manufacture("C").Show();
    }catch (NullPointerException e){
      System.out.println("没有这一类产品");
    }

    //客户要产品D
    try {
      mFactory.Manufacture("D").Show();
    }catch (NullPointerException e){
      System.out.println("没有这一类产品");
    }
  }
}

生产出了产品A
生产出了产品C
生产出了产品C
没有这一类产品