1. @FunctionalInterface能简化代码，解决匿名内部类代码冗余，适用单一接口，或被default和static修饰
public interface ObtainxxStatus {
/**
* description 获取进展状态和节点信息
*
* @param sellerId sellerId
* @param planCode planCode
* @return List<CooperationVO>
**/
List<CooperationVO> getxxStatus(Long sellerId,String planCode);
}
2.写法：拷贝小括号，写死右箭头，落地大括号，λ
ObtainxxStatus cooStatus = (Long sellerIds, String planCodes) -> {
List<CooperationVO> list = getCooperationList(sellerIds, planCodes);
if (list != null) {
return list;
}
logger.error("ObtainxxStatus null list");
return null;
};
