策略模式（简单例子）

public class huanjing {sageInter sage;    public sageInter getSage() {return sage;}public void setSage(sageInter sage) {this.sage = sage;}public huanjing(sageInter sage){    this.sage=sage;    }}

?环境类

public interface sageInter {     public int come(int a,int b);}

?接口

public class chu implements sageInter {@Overridepublic int come(int a, int b) {// TODO Auto-generated method stubreturn 1/b;}}

?实现类

public static void main(String[] args) {// TODO Auto-generated method stub         jian j=new jian();         huanjing hj=new huanjing(j);        int s= hj.getSage().come(10, 11);        System.out.println(s);}

?调用类