【三十四】springboot+easyRule初识规则引擎

        代码场景：厂里有几个员工，现在厂长颁布了新的厂规关于薪资发放，如下：

• 1、加班时长超过80小时的，一个小时10块钱；不满80小时的，不算加班。
• 2、上班打卡迟到3次以下的不扣钱，3次以上的一次扣100。

        针对如上需求，是不是就可以通过写if-if判断来处理，但是如果规则变化呢，老板想只要迟到1次就扣1000，或者只要加班就100块钱一个小时呢，是不是只有改代码升级。 本章针对这个问题，通过规则引擎实现这个场景，实现规则配置化。

目录

一、准备工作

二、注解方式实现

三、yml配置方式实现

---

一、准备工作

1、表

2、依赖

<dependency><groupId>org.jeasy</groupId><artifactId>easy-rules-core</artifactId><version>4.1.0</version></dependency><dependency><groupId>org.jeasy</groupId><artifactId>easy-rules-mvel</artifactId><version>4.1.0</version></dependency><dependency><groupId>org.jeasy</groupId><artifactId>easy-rules-spel</artifactId><version>4.1.0</version></dependency><dependency><groupId>org.jeasy</groupId><artifactId>easy-rules-jexl</artifactId><version>4.1.0</version></dependency>

二、注解方式实现

1、编写目的场景的规则

@Rule(name = "无效加班", description = "加班费的结算", priority = 1)
public class Rule1 {@Conditionpublic boolean when(@Fact("time") double time) {return time<=80;}@Actionpublic void then(@Fact("reason") StringBuffer reason) {reason.append("加班少于80小时，不发加班费;");}}

@Rule(name = "有效加班", description = "加班费的结算", priority = 2)
public class Rule2 {@Conditionpublic boolean when(@Fact("time") double time) {return time > 80;}@Actionpublic void then(@Fact("time") double time,@Fact("reason") StringBuffer reason,@Fact("money") AtomicDouble money) {money.set(money.get()+10*(time-80));reason.append("加班费:").append(10*(time-80)).append(";");}}

@Rule(name = "迟到警告", description = "迟到的惩罚", priority = 3)
public class Rule3 {@Conditionpublic boolean when(@Fact("count") int count) {return count<=3;}@Actionpublic void then(@Fact("count") int count, @Fact("money") AtomicDouble money, @Fact("reason") StringBuffer reason) {reason.append("迟到小于3次，暂时不扣钱;");}}

@Rule(name = "迟到扣钱", description = "迟到的惩罚", priority = 3)
public class Rule4 {@Conditionpublic boolean when(@Fact("count") int count) {return count>3;}@Actionpublic void then(@Fact("count") int count, @Fact("money") AtomicDouble money, @Fact("reason") StringBuffer reason) {money.set(money.get() - (count-3)*100);reason.append("迟到大于3次，扣钱:").append((count - 3) * 100).append(";");}}

• @Rule标识该类为规则类
• @Condition标识该方法为条件（一个rule类只能有一个） 
• @Action标识该方法为条件满足为true后的执行方法
• @Fact代表事实，标识入参，可以通过Fact的key值获取值
• priority标识该rule的执行顺序

2、编写接口

@Slf4j
@Api(tags = "牛马管理接口")
@RestController
@RequestMapping("/staffController")
@AllArgsConstructor
public class StaffController {private final StaffMapper staffMapper;@ApiOperation(value = "计算工资")@PostMapping("/getSalary")public BaseResponse<Integer> getSalary() {// 初始化规则引擎RulesEngineParameters parameters = new RulesEngineParameters().skipOnFirstAppliedRule(false);DefaultRulesEngine engine = new DefaultRulesEngine(parameters);engine.registerRuleListener(new MyRuleListener());// 注册规则进入引擎Rules rules = new Rules();rules.register(new Rule1());rules.register(new Rule2());rules.register(new Rule3());rules.register(new Rule4());//UnitRuleGroup unitRuleGroup = new UnitRuleGroup("myUnitRuleGroup", "myUnitRuleGroup");//unitRuleGroup.addRule(new Rule1());//unitRuleGroup.addRule(new Rule2());//unitRuleGroup.addRule(new Rule3());//unitRuleGroup.addRule(new Rule4());//rules.register(unitRuleGroup);List<Staff> list = staffMapper.selectList(new QueryWrapper<>());for (Staff staff : list) {AtomicDouble money = new AtomicDouble((Double.parseDouble(staff.getMoney())));double beforeMoney = money.get();StringBuffer reason = new StringBuffer();Facts facts = new Facts();facts.put("time", Double.parseDouble(staff.getTime()));facts.put("count", staff.getCount());facts.put("money", money);facts.put("reason", reason);engine.fire(rules, facts);Staff staffNew = staffMapper.selectById(staff.getId());staffNew.setFinalMoney(facts.get("money").toString());staffNew.setDetail(reason.toString());staffMapper.updateById(staffNew);}return RespGenerator.returnOK("成功");}}

3、测试

根据结果可以看到数据正确。

现在假设我们厂长更改了需求：现在只要迟到超过3次，都没有加班费。

        如上代码可以根据实际情况改造一下，当有需求所有规则要么全部执行，要么全部不执行时（只要有一个不满足就全部跳过执行），可以选用另一种方式UnitRuleGroup，改造如下：

@ApiOperation(value = "计算工资")@PostMapping("/getSalary")public BaseResponse<Integer> getSalary() {// 初始化规则引擎RulesEngineParameters parameters = new RulesEngineParameters().skipOnFirstAppliedRule(false);DefaultRulesEngine engine = new DefaultRulesEngine(parameters);engine.registerRuleListener(new MyRuleListener());// 注册规则进入引擎Rules rules = new Rules();//rules.register(new Rule1());//rules.register(new Rule2());//rules.register(new Rule3());//rules.register(new Rule4());UnitRuleGroup unitRuleGroup = new UnitRuleGroup("myUnitRuleGroup", "myUnitRuleGroup");//unitRuleGroup.addRule(new Rule1());unitRuleGroup.addRule(new Rule2());unitRuleGroup.addRule(new Rule3());//unitRuleGroup.addRule(new Rule4());rules.register(unitRuleGroup);List<Staff> list = staffMapper.selectList(new QueryWrapper<>());for (Staff staff : list) {AtomicDouble money = new AtomicDouble((Double.parseDouble(staff.getMoney())));double beforeMoney = money.get();StringBuffer reason = new StringBuffer();Facts facts = new Facts();facts.put("time", Double.parseDouble(staff.getTime()));facts.put("count", staff.getCount());facts.put("money", money);facts.put("reason", reason);engine.fire(rules, facts);Staff staffNew = staffMapper.selectById(staff.getId());staffNew.setFinalMoney(facts.get("money").toString());staffNew.setDetail(reason.toString());staffMapper.updateById(staffNew);}return RespGenerator.returnOK("成功");}

结果如下：

 可以看到赵四加班了一个小时也没有加班费了。

三、yml配置方式实现

1、增加配置文件

---
name: '无效加班'
description: '加班费的结算'
priority: 1
condition: "time<=80"
actions:- "reason.append('加班少于80小时，不发加班费;');"
---
name: '有效加班'
description: '加班费的结算'
priority: 2
condition: "time>80"
actions:- "money.set(money.get()+10*(time-80));reason.append('加班费:').append(10*(time-80)).append(';');"
---
name: '迟到警告'
description: '迟到的惩罚'
priority: 1
condition: "count<=3"
actions:- "reason.append('迟到小于3次，暂时不扣钱;');"
---
name: '迟到扣钱'
description: '迟到的惩罚'
priority: 2
condition: "count>3"
actions:- "money.set(money.get() - (count-3)*1000);reason.append('迟到大于3次，扣钱:').append((count - 3) * 1000).append(';');"

每个rule之间通过---进行分割，可以在condition和actions下写java代码。 

2、改造接口

@ApiOperation(value = "计算工资")@PostMapping("/getSalary")public BaseResponse getSalary() throws Exception {// 初始化规则引擎RulesEngineParameters parameters = new RulesEngineParameters().skipOnFirstAppliedRule(false);DefaultRulesEngine engine = new DefaultRulesEngine(parameters);engine.registerRuleListener(new MyRuleListener());// 注册规则进入引擎MVELRuleFactory ruleFactory = new MVELRuleFactory(new YamlRuleDefinitionReader());Rules rules = ruleFactory.createRules(new BufferedReader(new InputStreamReader(Objects.requireNonNull(this.getClass().getClassLoader().getResourceAsStream("rules.yml")))));List<Staff> list = staffMapper.selectList(new QueryWrapper<>());for (Staff staff : list) {AtomicDouble money = new AtomicDouble((Double.parseDouble(staff.getMoney())));double beforeMoney = money.get();StringBuffer reason = new StringBuffer();Facts facts = new Facts();facts.put("time", Double.parseDouble(staff.getTime()));facts.put("count", staff.getCount());facts.put("money", money);facts.put("reason", reason);engine.fire(rules, facts);Staff staffNew = staffMapper.selectById(staff.getId());staffNew.setFinalMoney(facts.get("money").toString());staffNew.setDetail(reason.toString());staffMapper.updateById(staffNew);}return RespGenerator.returnOK("成功");}

 

假设当我们调整加班费时（1块钱一个小时），修改配置即可。

name: '有效加班'
description: '加班费的结算'
priority: 2
condition: "time>80"
actions:- "money.set(money.get()+1*(time-80));reason.append('加班费:').append(1*(time-80)).append(';');"