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设计模式

1.单例模式

2.工厂模式
  简介:
  核心思想:有一个专门的类来负责创建实例的过程。
  优缺点:模式的核心是工厂类,这个类负责产品的创建,而客户端可以免去产品创建的责任,这实现了责任的分割。但由于工厂类集中了所有产品创建逻辑的,如果不能正常工作的话会对系统造成很大的影响。如果增加新产品必须修改工厂角色的源码。
  设计:1个接口类,若干个实现该接口的实现类,1个工厂类(工厂类实行调控功能,负责判断、控制哪个实现类被执行。工厂方法一般都是static的)。

代码:

public interface Fruit {      void grow();//生长     void harvest();//收获      void plant();//种植}public class Apple implements Fruit{     private int treeAge;    public void grow() {         System.out.println("Apple is growing");    }    public void harvest() {         System.out.println("Apple has been harvested");    }    public void plant() {         System.out.println("Apple has been planted");    }    public int getTreeAge() {          return treeAge;     }    public void setTreeAge(int age) {          this.treeAge=age;     }}public class Grape implements Fruit {     private boolean seedless;     public void grow() {          System.out.println("Apple is growing");     }     public void harvest() {          System.out.println("Apple has been harvested");     }     public void plant() {          System.out.println("Apple has been planted");     }     public boolean getSeedless() {          return seedless;     }     public void setSeedless(boolean seed) {          this.seedless=seed;     }}public class FruitGardener {     public static Fruit factory(String which) throws BadFruitException {          if(which.equalsIgnoreCase("apple搜索"))  {               return new Apple();          } else if (which.equalsIgnoreCase("grape"))  {               return new Grape();          }  else {               throw new BadFruitException("Bad Fruit request");          }        }}public class BadFruitException extends Exception{     public BadFruitException(String msg) {          super(msg);     }}public static void main(String[] args) {     try {          FruitGardener.factory("apple");          FruitGardener.factory("grape");     } catch(BadFruitException e) {                  System.out.println(e);     }     }

 

设计模式