规则引擎由推理引擎发展而来，是一种嵌入在应用程序中的组件，
实现了将业务决策从应用程序代码中分离出来，并使用预定义的语义模块编写业务决策。
接受数据输入，解释业务规则，并根据业务规则做出业务决策。

表达式语言 expression language
MVEL  MVFLEX Expression Language
SpEL  Spring表达式语言
JEXL  Java Expression Language

You can build a simple rules engine yourself. 
All you need is to create a bunch of objects with conditions and actions, 
store them in a collection, and run through them to evaluate the conditions and execute the actions.
This is exactly what Easy Rules does, 
it provides the Rule abstraction to create rules with conditions and actions, 
and the RulesEngine API that runs through a set of rules to evaluate conditions and execute actions.

Easy Rules is a simple yet powerful Java rules engine providing the following features:
Lightweight framework and easy to learn API
POJO based development
Useful abstractions to define business rules and apply them easily
The ability to create composite rules from primitive ones
The ability to define rules using an Expression Language (Like MVEL, SpEL and JEXL)

40岁以上中年人就业方向
吉祥三保+铁人三项
吉祥三保：保安+保洁+保险
铁人三项：滴滴+快递+外卖

熬夜对身体不好，所以我建议你通宵

强者从不抱怨环境，因为环境就是他们搞烂的

青菜香菇菜饭 炒饭

布林波段
价格突破上轨再跌破上轨做空看空
价格跌破下轨再突破下轨做多看多
上轨---中轨（强势区域）
中轨---下轨（弱势区域）

低空经济，是以航空器为主、低空活动为牵引，多产业融合的新经济形态。
以民用有人驾驶和无人驾驶航空器为主，以载人、载货及其他作业等多场景低空飞行活动为牵引，辐射带动相关领域融合发展的综合性经济形态。