标签：des style blog color os io strong ar art
工厂模式：专门负责将大量有共同接口的类实例化，工厂模式可以动态的决定将哪一个类实例化，不必事先知道每次要实例化哪一个类。工厂模式有以下几种形态：
1.简单工厂模式UML类图如图所示：
代码：
Fruit 抽象产品:
package com.lp.ecjtu.SimpleFactory; public interface Fruit { /** * 种植 */ public void plant(); /** * 生长 */ public void grow(); /** * 收货 */ public void harvest(); }
具体产品：这里包括Apple，Orange，Grape：
package com.lp.ecjtu.SimpleFactory; public class Apple implements Fruit{ @Override public void plant() { // TODO Auto-generated method stub System.out.println("Apples have been planted!"); } @Override public void grow() { // TODO Auto-generated method stub System.out.println("Apples is growing!"); } @Override public void harvest() { // TODO Auto-generated method stub System.out.println("Apples have been harvested!"); } }
package com.lp.ecjtu.SimpleFactory; public class Orange implements Fruit { @Override public void plant() { // TODO Auto-generated method stub System.out.println("Oranges have been planted!"); } @Override public void grow() { // TODO Auto-generated method stub System.out.println("Oranges is growing!"); } @Override public void harvest() { // TODO Auto-generated method stub System.out.println("Oranges have been harvested!"); } }
package com.lp.ecjtu.SimpleFactory; public class Grape implements Fruit { private boolean seedless; public boolean isSeedless() { return seedless; } public void setSeedless(boolean seedless) { this.seedless = seedless; } public void plant() { // TODO Auto-generated method stub System.out.println("Grapes have been planted!"); } public void grow() { // TODO Auto-generated method stub System.out.println("Grapes is growing!"); } public void harvest() { // TODO Auto-generated method stub System.out.println("Grapes have been growed!"); } }
工厂类：工厂模式的核心
package com.lp.ecjtu.SimpleFactory; public class FruitGarden { public FruitGarden(){} public static Fruit factoryFruit(String which) throws BadFruitException { if(which.equalsIgnoreCase("apple")){ return new Apple(); }else if(which.equalsIgnoreCase("orange")){ return new Orange(); }else if(which.equalsIgnoreCase("grape")){ return new Grape(); }else{ throw new BadFruitException("bad fruit"); } } }
FruitClient :
package com.lp.ecjtu.SimpleFactory; public class FruitClient { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub try { Fruit f = FruitGarden.factoryFruit("apple"); f.plant(); f.grow(); f.harvest(); System.out.println("********************************"); Fruit o = FruitGarden.factoryFruit("orange"); o.grow(); o.harvest(); o.plant(); } catch (BadFruitException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }
运行输出：
Apples have been planted!
Apples is growing!
Apples have been harvested!
********************************
Oranges is growing!
Oranges have been harvested!
Oranges have been planted!
简单工厂模式的优点与缺陷：
优点：模式的核心是工厂，这个类含有必要的判断逻辑，可以决定在什么时候创建哪一个产品的实例。而客户端可以免除直接创建产品对象的责任，而仅仅负责"消费"产品。实现了对责任的额分割。
缺陷：工厂类是一个全能类，像上帝类，里面的方法是静态的，无法由子类继承，扩展性比较差，当有新的产品加入到系统中去，就需要修改工厂类。对"开-闭"
2.工厂方法设计模式（多态工厂模式）
工厂方法设计模式：弥补了简单工厂对“开-闭”原则支持不够的缺点，核心的工厂类不在负责所有产品的创建，而将具体创建工作交给了子类去做，这个核心类变成了一个抽象工厂角色。仅负责给出具体工厂子类必须的实现接口，而不接触那个产品类应该被实例化的这种细节。这样当系统需要加入新的产品的时候，不需要修改客户端，也没必要修改抽象工厂类或者其他已有的具体工厂角色，只需要向系统加入一个产品类以及它对应的工厂类。
下面我们对上面的水果类作物系统进行优化，在那个系统中有一个全知全能的园丁角色（FruitGarden），控制所有作物的种植，生长，收货。现在这个农场的规模变大了，而同时发生的是管理更专业化了。过去的全能人物没有了，每一种弄作物都有专门的园丁管理，形成规模化生产和专业化生产。
下图为工厂方法模式UML类图
代码实现：
抽象工厂角色：FruitGarden
package com.lp.ecjtu.FactoryMethod; public interface FruitGarden { /** * 工厂方法，抽象工厂角色 * @return */ public Fruit factory(); }
具体工厂角色：AppleGarden，GrapeGarden，OrangeGarden
package com.lp.ecjtu.FactoryMethod; public class AppleGarden implements FruitGarden{ /** * 工厂方法，抽象工厂角色 * @return */ public Fruit factory() { return new Apple(); } }
package com.lp.ecjtu.FactoryMethod; public class OrangeGarden implements FruitGarden{ /** * 工厂方法，抽象工厂角色 * @return */ public Fruit factory() { return new Orange(); } }
package com.lp.ecjtu.FactoryMethod; public class GrapeGarden implements FruitGarden{ /** * 工厂方法，抽象工厂角色 * @return */ public Fruit factory() { return new Grape(); } }
抽象产品角色：Fruit
package com.lp.ecjtu.FactoryMethod; public interface Fruit { /** * 种植 */ public void plant(); /** * 生长 */ public void grow(); /** * 收货 */ public void harvest(); }
具体产品角色：Apple，Orange，Grape
package com.lp.ecjtu.FactoryMethod; public class Apple implements Fruit { private int treeAge; public int getTreeAge() { return treeAge; } public void setTreeAge(int treeAge) { this.treeAge = treeAge; } @Override public void plant() { System.out.println("Apples have been planted!"); } @Override public void grow() { // TODO Auto-generated method stub System.out.println("Apples is growing!"); } @Override public void harvest() { // TODO Auto-generated method stub System.out.println("Apples have been harvested!"); } }
package com.lp.ecjtu.FactoryMethod; public class Orange implements Fruit { @Override public void plant() { System.out.println("Oranges have been planted!"); } @Override public void grow() { // TODO Auto-generated method stub System.out.println("Oranges is growing!"); } @Override public void harvest() { // TODO Auto-generated method stub System.out.println("Oranges have been harvested!"); } }
package com.lp.ecjtu.FactoryMethod; public class Grape implements Fruit { private String seedLess; public String isSeedLess() { return seedLess; } public void setSeedLess(String seedLess) { this.seedLess = seedLess; } @Override public void plant() { System.out.println("Grapes have been planted!"); } @Override public void grow() { // TODO Auto-generated method stub System.out.println("Grapes is growing!"); } @Override public void harvest() { // TODO Auto-generated method stub System.out.println("Grapes have been harvested!"); } }
水果Client：FruitClient
package com.lp.ecjtu.FactoryMethod; public class FruitClient { /** * @param args */ public static void main(String[] args) { FruitGarden fa = new AppleGarden(); Fruit f = fa.factory(); f.plant(); f.grow(); f.harvest(); System.out.println("********************************"); FruitGarden fo = new OrangeGarden(); Fruit o = fo.factory(); o.grow(); o.harvest(); o.plant(); System.out.println("********************************"); FruitGarden fg = new GrapeGarden(); Fruit g = fg.factory(); g.grow(); g.harvest(); g.plant(); } }
输出结果：
Apples have been planted!
Apples is growing!
Apples have been harvested!
********************************
Oranges is growing!
Oranges have been harvested!
Oranges have been planted!
********************************
Grapes is growing!
Grapes have been harvested!
Grapes have been planted!
标签：des style blog color os io strong ar art
原文地址：http://www.cnblogs.com/200911/p/3935383.html
