35、Activiti整合规则引擎Drools

日常生活是由规则驱动的。红灯停绿灯行，这是我们的交通规则；我们站着往上跳，最终还是要落下来，这是地球的引力规则。规则在生活中无处不在。软件开发中我们也需要规则，满足什么规则应该进入什么分支。如果做过风控系统，就知道风控系统里存在非常多的规则（比如：age < 16 || age > 50 -> REJECT ）。最便捷的实现就是用 if-else 来写，但是随着规则的增加以及需求的变动，代码将变得越来越难阅读和理解，如果再去修改这些代码，然后测试不够充分的话，将产生严重的生产事故。这时候就要引入Drools等规则引擎了。Drools就是为了解决业务代码和业务规则分离的引擎。

要使用Drools规则引擎，需要先安装安装JBoss Drools Support插件，这里就不多说怎么安装安装JBoss Drools Support插件。下载地址如下：

https://download.jboss.org/drools/release/7.3.0.Final/droolsjbpm-tools-distribution-7.3.0.Final.zip

1、 新建项目sc-activiti-drools，对应的pom.xml文件如下

<?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 <modelVersion>4.0.0</modelVersion>
 <groupId>com.sc</groupId>
 <artifactId>sc-activiti-drools</artifactId>
 <version>0.0.1-SNAPSHOT</version>
 <name>sc-activiti-drools</name>
 <!-- FIXME change it to the project's website -->
 <url>http://www.example.com</url>
 <properties>
 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 <maven.compiler.source>1.8</maven.compiler.source>
 <maven.compiler.target>1.8</maven.compiler.target>
 </properties>
 <parent>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-parent</artifactId>
 <version>2.0.4.RELEASE</version>
 </parent>
 <dependencyManagement>
 <dependencies>
 <dependency>
 <groupId>org.springframework.cloud</groupId>
 <artifactId>spring-cloud-dependencies</artifactId>
 <version>Finchley.RELEASE</version>
 <type>pom</type>
 <scope>import</scope>
 </dependency>
 </dependencies>
 </dependencyManagement>
 <dependencies>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-web</artifactId>
 </dependency>
 <dependency>
 <groupId>org.activiti</groupId>
 <artifactId>activiti-engine</artifactId>
 <version>6.0.0</version>
 </dependency>
 <dependency>
 <groupId>org.activiti</groupId>
 <artifactId>activiti-spring</artifactId>
 <version>6.0.0</version>
 </dependency>
 <dependency>
 <groupId>mysql</groupId>
 <artifactId>mysql-connector-java</artifactId>
 <scope>runtime</scope>
 </dependency>
 <dependency>
 <groupId>org.drools</groupId>
 <artifactId>drools-core</artifactId>
 <version>7.0.0.Final</version>
 </dependency>
 <dependency>
 <groupId>org.drools</groupId>
 <artifactId>drools-compiler</artifactId>
 <version>7.0.0.Final</version>
 </dependency>
 <dependency>
 <groupId>org.drools</groupId>
 <artifactId>knowledge-api</artifactId>
 <version>6.5.0.Final</version>
 </dependency>
 </dependencies>
 <build>
 <pluginManagement><!-- lock down plugins versions to avoid using Maven 
 defaults (may be moved to parent pom) -->
 <plugins>
 <plugin>
 <artifactId>maven-clean-plugin</artifactId>
 <version>3.0.0</version>
 </plugin>
 <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
 <plugin>
 <artifactId>maven-resources-plugin</artifactId>
 <version>3.0.2</version>
 </plugin>
 <plugin>
 <artifactId>maven-compiler-plugin</artifactId>
 <version>3.7.0</version>
 </plugin>
 <plugin>
 <artifactId>maven-surefire-plugin</artifactId>
 <version>2.20.1</version>
 </plugin>
 <plugin>
 <artifactId>maven-jar-plugin</artifactId>
 <version>3.0.2</version>
 </plugin>
 <plugin>
 <artifactId>maven-install-plugin</artifactId>
 <version>2.5.2</version>
 </plugin>
 <plugin>
 <artifactId>maven-deploy-plugin</artifactId>
 <version>2.8.2</version>
 </plugin>
 </plugins>
 </pluginManagement>
 </build>
 </project>

2、新建spring配置文件application.yml

spring:
 datasource:
 driver-class-name: com.mysql.jdbc.Driver
 url: jdbc:mysql://127.0.0.1:3306/sc?characterEncoding=utf8&useSSL=true
 username: root
 password: root
 activiti:
 check-process-definitions: false #自动部署验证设置:true-开启（默认）、false-关闭
 jpa:
 properties:
 hibernate:
 hbm2ddl:
 auto: update
 show-sql: true
 server:
 port: 8081
 context-path: /
 session:
 timeout: 10
 tomcat:
 uri-encoding: UTF-8

3、新建activiti对应的配置文件activiti.cfg.xml

<?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
 <bean id="dataSource" class="org.springframework.jdbc.datasource.SimpleDriverDataSource">
 <property name="driverClass" value="com.mysql.jdbc.Driver" />
 <property name="url" value="jdbc:mysql://localhost:3306/act?useUnicode=true&characterEncoding=UTF-8" />
 <property name="username" value="root" />
 <property name="password" value="root" />
 </bean>
 <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
 <property name="dataSource" ref="dataSource" />
 </bean>
 <bean id="processEngineConfiguration" class="org.activiti.spring.SpringProcessEngineConfiguration">
 <property name="dataSource" ref="dataSource" />
 <property name="transactionManager" ref="transactionManager" />
 <property name="databaseSchemaUpdate" value="true" />
 <property name="customPostDeployers">
 <list> 
 <bean class="org.activiti.engine.impl.rules.RulesDeployer" />
 </list> 
 </property>
 <!-- 
 <property name="deploymentResources" value="classpath*:/bpmn/*.bpmn" /> 
 -->
 </bean>
 <bean id="processEngine" class="org.activiti.spring.ProcessEngineFactoryBean">
 <property name="processEngineConfiguration" ref="processEngineConfiguration" />
 </bean>
 <bean id="repositoryService" factory-bean="processEngine" factory-method="getRepositoryService" />
 <bean id="runtimeService" factory-bean="processEngine" factory-method="getRuntimeService" />
 <bean id="taskService" factory-bean="processEngine" factory-method="getTaskService" />
 <bean id="historyService" factory-bean="processEngine" factory-method="getHistoryService" />
 <bean id="managementService" factory-bean="processEngine" factory-method="getManagementService" />
 </beans>

4、新建请假流程对应的bpmn文件如下

<?xml version="1.0" encoding="UTF-8"?>
 <definitions xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"
 xmlns:activiti="http://activiti.org/bpmn" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI"
 xmlns:omgdc="http://www.omg.org/spec/DD/20100524/DC" xmlns:omgdi="http://www.omg.org/spec/DD/20100524/DI"
 typeLanguage="http://www.w3.org/2001/XMLSchema" expressionLanguage="http://www.w3.org/1999/XPath"
 targetNamespace="http://www.activiti.org/test">
 <process id="leave" name="请假审批" isExecutable="true">
 <startEvent id="startevent1" name="Start"></startEvent>
 <endEvent id="endevent1" name="End"></endEvent>
 <userTask id="usertask1" name="部门经理审批"></userTask>
 <businessRuleTask id="businessruletask1" name="天数判断" activiti:ruleVariablesInput="${leave}" activiti:rules="leave1,leave2" activiti:resultVariable="reason"></businessRuleTask>
 <serviceTask id="servicetask1" name="获取变量" activiti:class="sc.ad.service.DroolsService"></serviceTask>
 <userTask id="usertask2" name="HR审批"></userTask>
 <sequenceFlow id="flow1" sourceRef="startevent1" targetRef="usertask1"></sequenceFlow>
 <sequenceFlow id="flow2" sourceRef="usertask1" targetRef="businessruletask1"></sequenceFlow>
 <sequenceFlow id="flow3" sourceRef="businessruletask1" targetRef="servicetask1"></sequenceFlow>
 <userTask id="usertask3" name="总经理审批"></userTask>
 <sequenceFlow id="flow4" sourceRef="servicetask1" targetRef="usertask3">
 <conditionExpression xsi:type="tFormalExpression"><![CDATA[${reason[0].total >= 10}]]></conditionExpression>
 </sequenceFlow>
 <sequenceFlow id="flow5" sourceRef="servicetask1" targetRef="usertask2">
 <conditionExpression xsi:type="tFormalExpression"><![CDATA[${reason[0].total < 10}]]></conditionExpression>
 </sequenceFlow>
 <sequenceFlow id="flow6" sourceRef="usertask3" targetRef="usertask2"></sequenceFlow>
 <sequenceFlow id="flow7" sourceRef="usertask2" targetRef="endevent1"></sequenceFlow>
 </process>
 </definitions>

bpmn文件对应的图如下

5、新建规则文件leave.drl

package sc.ad;
 import sc.ad.model.Leave;
 rule "leave1"
 when
 u : Leave(day < 3);
 then
 u.setTotal(u.getDay() + 2);
 end
 rule "leave2"
 when
 u : Leave(day >= 3);
 then
 u.setTotal(u.getDay() + 5);
 end

对应的图如下

6、新建springboot启动类文件

package sc.ad;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.context.annotation.ImportResource;
 @SpringBootApplication
 @ImportResource("activiti.cfg.xml")
 public class ActivitiDroolsApp {
 public static void main(String[] args)
 {
 SpringApplication.run(ActivitiDroolsApp.class, args);
 }
 }

7、新建一个controller，用来发起请假请求

package sc.ad.controller;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import org.activiti.engine.RepositoryService;
 import org.activiti.engine.RuntimeService;
 import org.activiti.engine.TaskService;
 import org.activiti.engine.repository.Deployment;
 import org.activiti.engine.repository.DeploymentBuilder;
 import org.activiti.engine.repository.ProcessDefinition;
 import org.activiti.engine.runtime.ProcessInstance;
 import org.activiti.engine.task.Task;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 import sc.ad.model.Leave;
 @RestController
 public class ADController {
 @Autowired
 private RepositoryService repositoryService;
 @Autowired
 private RuntimeService runtimeService;
 @Autowired
 private TaskService taskService;
 // @RequestMapping("/ad")
 // public void ad() {
 //
 // // 根据bpmn文件部署流程
 // Deployment deployment = repositoryService.createDeployment()
 // .addClasspathResource("holiday.bpmn").deploy();
 // // 获取流程定义
 // ProcessDefinition processDefinition = repositoryService
 // .createProcessDefinitionQuery()
 // .deploymentId(deployment.getId()).singleResult();
 // // 启动流程定义，返回流程实例
 // ProcessInstance pi = runtimeService
 // .startProcessInstanceById(processDefinition.getId());
 // String processId = pi.getId();
 // System.out.println("流程创建成功，当前流程实例ID：" + processId);
 //
 // Task task = taskService.createTaskQuery().processInstanceId(processId)
 // .singleResult();
 // System.out.println("第一次执行前，任务名称：" + task.getName());
 // taskService.complete(task.getId());
 //
 // task = taskService.createTaskQuery().processInstanceId(processId)
 // .singleResult();
 // System.out.println("第二次执行前，任务名称：" + task.getName());
 // taskService.complete(task.getId());
 //
 // task = taskService.createTaskQuery().processInstanceId(processId)
 // .singleResult();
 // System.out.println("task为null，任务执行完毕：" + task);
 // }
 @RequestMapping("/drl")
 public void drl() {
 /**
 * 注意这里：必须要把drl文件一起deploy
 */
 DeploymentBuilder deploy = repositoryService.createDeployment();
 deploy.addClasspathResource("leave.bpmn").addClasspathResource("leave.drl");
 deploy.deploy();
 ProcessInstance pi = runtimeService.startProcessInstanceByKey("leave");
 Map<String, Object> vars = new HashMap<String, Object>(); 
 vars.put("leave", new Leave("白展堂", 12));
 /**
 * 当前任务
 */
 List<Task> tasks = taskService.createTaskQuery().processInstanceId(pi.getId()).list();
 for(Task task : tasks)
 {
 System.out.println(task.getId() + " , " + task.getName());
 taskService.complete(task.getId(), vars);
 }
 /**
 * 下一步任务
 */
 tasks = taskService.createTaskQuery().processInstanceId(pi.getId()).list();
 for(Task task : tasks)
 {
 System.out.println(task.getId() + " , " + task.getName());
 }
 }
 }

8、启动并验证规则是否生效

从日志中看启动成功

访问http://127.0.0.1:8081/drl后，再次查看日志：

把修改controller的如下代码

vars.put("leave", new Leave("白展堂", 12));

改成

vars.put("leave", new Leave("乔峰", 2));

可以看到规则文件的规则已经生效：