设计模式之略见一斑(策略模式strategy)

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/** * 策略 * @author Administrator * */public class Stratery {protected String stratery;public Stratery(String stratery){this.stratery = stratery;}}/** * 策略1 * @author Administrator * */public class Stratery1 extends Stratery {public Stratery1(String stratery){super(stratery);}}/** * 策略2 * @author Administrator * */public class Stratery2 extends Stratery{public Stratery2(String stratery){super(stratery);}}/** * 策略3 * @author Administrator * */public class Stratery3 extends Stratery{public Stratery3(String stratery){super(stratery);}}

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传统的实现方法如下：

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    public static Stratery get(int cas){    switch (cas) {case 1:return new Stratery1("策略1");case 2:return new Stratery2("策略2");case 3:return new Stratery1("策略3");default:return null;}    }

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根据用户的情况返回。

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下面仅对上面的代码进行重构，使其成为strategy模式

定义一个共同的接口:

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public interface Advisor {    public Stratery getAdvisor();}

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每个策略方案都实现这个接口:

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/** * 策略1 * @author Administrator * */public class Stratery1 extends Stratery implements Advisor{public Stratery1(String stratery){super(stratery);}public Stratery1 getAdvisor() {// TODO Auto-generated method stubreturn this;}public String toString(){return stratery;}}

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最后利用接口实现策略调用：

public class New {public static Advisor getAdvisor(int cas) {switch (cas) {case 1:return new Stratery1("策略1").getAdvisor();case 2:return new Stratery2("策略2").getAdvisor();case 3:return new Stratery3("策略3").getAdvisor();default:return null;}}public static void main(String[] args) {Advisor a = getAdvisor(1);System.out.println(a);}}

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重构的核心思想就是：将一个操作分布在一组相关的类中。

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1 楼 EyejavaLi 2010-03-19 想请问下 不知道这样添加一个接口的重构有什么好处？