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&amp;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>
                <busine***uleTask?id="busine***uletask1"?name="天数判断"?activiti:ruleVariablesInput="${leave}"?activiti:rules="leave1,leave2"?activiti:resultVariable="reason"></busine***uleTask>
                <serviceTask?id="servicetask1"?name="获取变量"?activiti:class="sc.ad.service.DroolsService"></serviceTask>
                <userTask?id="usertask2"?name="HR审批"></userTask>
                <sequenceFlow?id="flow1"?sourceRef="startevent1"?targetRef="usertask1"></sequenceFlow>
                <sequenceFlow?id="flow2"?sourceRef="usertask1"?targetRef="busine***uletask1"></sequenceFlow>
                <sequenceFlow?id="flow3"?sourceRef="busine***uletask1"?targetRef="servicetask1"></sequenceFlow>
                <userTask?id="usertask3"?name="总经理审批"></userTask>
                <sequenceFlow?id="flow4"?sourceRef="servicetask1"?targetRef="usertask3">
                        <conditionExpression?xsi:type="tFormalExpression"><![CDATA[${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：

35、Activiti整合规则引擎Drools

原文：https://blog.51cto.com/13538361/2492026