策略模式

定义了算法家族, 分别封装起来, 让它们之间可以互相替换.

 //举例，假设有多个锦囊，没个锦囊中有不同的计谋/**  * 计谋接口 * @author fan * */public interface Scheme {   public String execute();}/** * 绿色计谋 * @author fan * */public class GreenSilk implements Scheme{    @Override    public String execute() {        // TODO Auto-generated method stub        return "run away";    }}/** * 红色计谋 * @author fan * */public class RedSilk implements Scheme{    @Override    public String execute() {        // TODO Auto-generated method stub        return "kill";    }}/** * 计谋持有者   锦囊 * @author fan * */public class SilkBox {    private Scheme scheme;    public SilkBox(Scheme scheme){        this.scheme=scheme;    }    public String execute() {        // TODO Auto-generated method stub        return this.scheme.execute();    }}//测试下public class Test {    public static void main(String[] args) {        SilkBox box = new SilkBox(new GreenSilk());        System.out.println(box.execute());        box = new SilkBox(new RedSilk());        System.out.println(box.execute());    }}//输出run awaykill