利用Java 8的Function接口来消灭if...else...

可以通过function函数和map，来消灭if...else...，通过此方式，达到的效果是：逻辑清楚，代码简洁，很大程度上解决了策略模式中弊端。

1.定义service类

public interface GrantTypeService {

    public String  beijing(String   resourceId);
    public String  shanghai(String  resourceId);
    public String  qingdao(String   resourceId);
}

2.定义ServiceImpl

public class GrantTypeServiceImpl implements GrantTypeService{

    public String  beijing(String   resourceId){
        return "北京";
    }

    public String  shanghai(String  resourceId){
        return "上海";
    }

    public String  qingdao(String   resourceId){
        return "青岛";
    }

}

3.通过map和function函数获取结果，此方式消灭了if...else...

    public String getResult(String resourceType) {
        Map> grantTypeMap = new HashMap<>();

        grantTypeMap.put("北京", resourceId -> grantTypeService.beijing(resourceId));
        grantTypeMap.put("上海",  resourceId-> grantTypeService.shanghai(resourceId));
        grantTypeMap.put("青岛", resourceId -> grantTypeService.qingdao(resourceId));
        Function result = grantTypeMap.get(resourceType);
        System.out.println("result" + result.toString());
        if (result != null) {
            System.out.println(result.apply(resourceType));
            return result.apply(resourceType);
        }
        return "找不到地方";
    }