Activiti是什么
- Activiti项目是一项新的基于Apache许可的开源BPM平台，从基础开始构建，旨在提供支持新的BPMN 2.0标准。
- Activiti是一种轻量级，可嵌入的BPM引擎，而且还设计适用于可扩展的云架构。 Activiti将提供宽松的Apache许可2.0，同时促进Activiti BPM引擎和BPMN 2.0的匹配。
使用工作流引擎的好处
工作流引擎最常见用于审批流程中，现在一线互联网公司也开始使用，并有快速推广的趋势，复杂繁多的业务流程如果采用if else实现那将是崩溃的，代码不可维护，业务流程在代码中可读性很差，所以高人设计了业务流程模型图示BPMN2.0,我们要做到就是把业务场景抽象为标准流程图，把流程图丢到流程引擎中按流程定义约定逐步流转，很显然扩展性和业务可描述性会好很多，所以工作流引擎主要用于解决复杂的业务，目前经常被提起的中台系统抽象业务为服务，也涉及大量智能的业务流程引擎做支撑。
如何快速上手
1.1 搭建流程引擎
我们在IDEA环境中使用 Spring Initializr引导我们创建一个标准工程，采用最新稳定版spring boot 2.0.2，Activiti 6.0,通过引入H2内存数据库，当程序启动Spring boot会基于自动配置原理给我们隐式的创建一个工作流引擎对象ProcessEngine，并把RuntimeService（控制流程运行时数据流转）等核心服务注册到 Spring 容器中，我们只需要 依赖注入使用即可。
1.2 开发
pom.xml如下所示:
// pom.xml
<?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.imooc.activiti</groupId>
<artifactId>activiti-demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>activiti-demo</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.2.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>24.0-jre</version>
</dependency>
<dependency>
<groupId>org.activiti</groupId>
<artifactId>activiti-spring-boot-starter-basic</artifactId>
<version>6.0.0</version>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
1.3 设计流程定义文件
流程定义文件xml如下:
// src/main/resources/processes/second_approve.bpmn
<?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" xmlns:tns="http://www.activiti.org/test" typeLanguage="http://www.w3.org/2001/XMLSchema" expressionLanguage="http://www.w3.org/1999/XPath" targetNamespace="http://www.activiti.org/test" id="m1528728906382" name="">
<process id="second_approve" name="二级审批流程" isExecutable="true" isClosed="false" processType="None">
<startEvent id="startEvent" name="开始"></startEvent>
<userTask id="submitForm" name="填写审批信息">
<extensionElements>
<activiti:formProperty id="message" name="申请信息" type="string" required="true"></activiti:formProperty>
<activiti:formProperty id="name" name="申请人姓名" type="string" required="true"></activiti:formProperty>
<activiti:formProperty id="submitTime" name="提交时间" type="date" datePattern="yyyy-MM-dd" required="true"></activiti:formProperty>
<activiti:formProperty id="submitType" name="确认申请" type="string" required="true"></activiti:formProperty>
</extensionElements>
</userTask>
<sequenceFlow id="flow1" sourceRef="startEvent" targetRef="submitForm"></sequenceFlow>
<exclusiveGateway id="decideSubmit" name="提交OR取消"></exclusiveGateway>
<sequenceFlow id="flow2" sourceRef="submitForm" targetRef="decideSubmit"></sequenceFlow>
<userTask id="tl_approve" name="主管审批">
<extensionElements>
<activiti:formProperty id="tlApprove" name="主管审批结果" type="string"></activiti:formProperty>
<activiti:formProperty id="tlMessage" name="主管备注" type="string" required="true"></activiti:formProperty>
</extensionElements>
</userTask>
<sequenceFlow id="flow3" sourceRef="decideSubmit" targetRef="tl_approve">
<conditionExpression xsi:type="tFormalExpression"><![CDATA[${submitType == "y" || submitType == "Y"}]]></conditionExpression>
</sequenceFlow>
<exclusiveGateway id="decideTLApprove" name="主管审批校验"></exclusiveGateway>
<sequenceFlow id="flow4" sourceRef="tl_approve" targetRef="decideTLApprove"></sequenceFlow>
<endEvent id="endEvent" name="结束"></endEvent>
<endEvent id="endEventCancel" name="取消"></endEvent>
<sequenceFlow id="flow8" sourceRef="decideSubmit" targetRef="endEventCancel">
<conditionExpression xsi:type="tFormalExpression"><![CDATA[${submitType == "n" || submitType == "N"}]]></conditionExpression>
</sequenceFlow>
<sequenceFlow id="flow9" sourceRef="decideTLApprove" targetRef="submitForm">
<conditionExpression xsi:type="tFormalExpression"><![CDATA[${tlApprove == "n" || tlApprove == "N"}]]></conditionExpression>
</sequenceFlow>
<sequenceFlow id="_2" sourceRef="decideTLApprove" targetRef="endEvent">
<conditionExpression xsi:type="tFormalExpression"><![CDATA[${tlApprove == "y" || tlApprove == "Y"}]]></conditionExpression>
</sequenceFlow>
</process>
</definitions>
流程执行我们使用了CommandLineRunner，这个类的事例会在Spring boot容器启动加载完成后直接运行
@Configuration
@Slf4jpublic class AutoConfigurationProcessDemo {
@Autowired private RuntimeService runtimeService;
@Autowired private TaskService taskService;
@Autowired private FormService formService;
/**
* 命令行执行
*
* @return
*/
@Bean
public CommandLineRunner commandLineRunner() {
return new CommandLineRunner() {
@Override
public void run(String... args) throws Exception {
log.info("启动我们的程序");
//启动运行流程
ProcessInstance processInstance = startProcessInstance("second_approve");
//处理流程任务
processTask(processInstance);
log.info("结束我们的程序");
}
};
} /**
* 处理流程任务
*
* @param processInstance
* @throws ParseException
*/
private void processTask(ProcessInstance processInstance) throws ParseException {
Scanner scanner = new Scanner(System.in);
while (processInstance != null && !processInstance.isEnded()) {
List<Task> list = taskService.createTaskQuery().list();
log.info("待处理任务数量 [{}]", list.size());
for (Task task : list) {
log.info("待处理任务 [{}]", task.getName());
Map<String, Object> variables = buildVariablesByScanner(scanner, task);
taskService.complete(task.getId(), variables);
processInstance = runtimeService
.createProcessInstanceQuery()
.processInstanceId(processInstance.getId())
.singleResult();
}
}
scanner.close();
} /**
* 从控制台获取变量
*
* @param scanner
* @param task
* @return
* @throws ParseException
*/
private Map<String, Object> buildVariablesByScanner(Scanner scanner, Task task) throws ParseException {
TaskFormData taskFormData = formService.getTaskFormData(task.getId());
List<FormProperty> formProperties = taskFormData.getFormProperties();
return buildVariablesByScanner(scanner, formProperties);
}
public static Map<String, Object> buildVariablesByScanner(Scanner scanner, List<FormProperty> formProperties) throws ParseException {
Map<String, Object> variables = Maps.newHashMap();
for (FormProperty property : formProperties) {
String line = null;
if (StringFormType.class.isInstance(property.getType())) {
log.info("请输入 {} ？", property.getName());
line = scanner.nextLine();
variables.put(property.getId(), line);
} else if (DateFormType.class.isInstance(property.getType())) {
log.info("请输入 {} ？ 格式 （yyyy-MM-dd）", property.getName());
line = scanner.nextLine();
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
Date date = dateFormat.parse(line);
variables.put(property.getId(), date);
} else {
log.info("类型暂不支持 {}", property.getType());
}
log.info("您输入的内容是 [{}]", line);
}
return variables;
} /**
* 获取流程实例
*
* @param processDefinitionId
* @return
*/
private ProcessInstance startProcessInstance(String processDefinitionId) {
ProcessInstance processInstance = runtimeService.startProcessInstanceByKey(processDefinitionId); log.info("启动流程 [{}]", processInstance.getProcessDefinitionKey()); return processInstance;
}
}
为了让控制台输出更清晰直观,让控制台日志仅仅输出message日志信息，忽略默认格式中日志级别时间信息等等。
//src/main/resources/application.yml
logging:
pattern:
console: "%m%n"
结语
我对activiti也是刚接触的小白。如有不正确之处，请不吝赐教。
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