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在企业级应用开发中，工作流管理系统如Flowable扮演着至关重要的角色，特别是在自动化业务流程、任务分配和审批流程设计上。动态创建流程模型，尤其是会签（Parallel Gateway）模型，是提升系统灵活性和响应速度的关键技术之一。本文将通过Java编程语言，深入探讨如何在运行时动态地创建包含会签环节的Flowable流程模型，并部署执行。请注意，以下示例基于Flowable 6.x版本。
1. 环境准备
首先，确保你的开发环境已配置好Flowable依赖。如果你使用Maven，可以在pom.xml中添加如下依赖：
<dependencies><dependency><groupId>org.flowable</groupId><artifactId>flowable-spring-boot-starter</artifactId><version>${flowable.version}</version></dependency><!-- 其他依赖... -->
</dependencies>
2. 动态模型创建基础
动态创建流程模型主要涉及Flowable的模型API。我们将使用BpmnModelInstance来构建模型，ModelBuilder来定义流程结构。
3. 创建会签流程模型
下面是一个简单的例子，展示如何用Java代码动态创建一个包含开始事件、并行网关（会签）、两个用户任务以及结束事件的基本流程模型。
import org.flowable.bpmn.model.BpmnModel;
import org.flowable.bpmn.model.EndEvent;
import org.flowable.bpmn.model.ParallelGateway;
import org.flowable.bpmn.model.Process;
import org.flowable.bpmn.model.SequenceFlow;
import org.flowable.bpmn.model.StartEvent;
import org.flowable.bpmn.model.UserTask;
import org.flowable.engine.RepositoryService;
import org.flowable.engine.repository.Deployment;// 假设repositoryService已经注入或获取到了
public void createParallelGatewayProcess() {// 创建BpmnModelInstanceBpmnModelInstance modelInstance = Bpmn.createEmptyModel();// 创建流程定义Process process = new Process();process.setId("parallelGatewayProcess");process.setName("Parallel Gateway Example");modelInstance.addProcess(process);// 添加开始事件StartEvent startEvent = modelInstance.newInstance(StartEvent.class);startEvent.setId("startEvent");process.addChildElement(startEvent);// 添加并行网关ParallelGateway parallelGateway = modelInstance.newInstance(ParallelGateway.class);parallelGateway.setId("parallelGateway");process.addChildElement(parallelGateway);// 连接开始事件到并行网关SequenceFlow flow1 = modelInstance.newInstance(SequenceFlow.class);flow1.setId("flow1");flow1.setSource(startEvent);flow1.setTarget(parallelGateway);modelInstance.addFlowElement(flow1);// 添加用户任务1UserTask userTask1 = modelInstance.newInstance(UserTask.class);userTask1.setId("userTask1");userTask1.setName("Task A");process.addChildElement(userTask1);// 添加用户任务2UserTask userTask2 = modelInstance.newInstance(UserTask.class);userTask2.setId("userTask2");userTask2.setName("Task B");process.addChildElement(userTask2);// 从并行网关到两个用户任务SequenceFlow flow2 = modelInstance.newInstance(SequenceFlow.class);flow2.setId("flow2");flow2.setSource(parallelGateway);flow2.setTarget(userTask1);modelInstance.addFlowElement(flow2);SequenceFlow flow3 = modelInstance.newInstance(SequenceFlow.class);flow3.setId("flow3");flow3.setSource(parallelGateway);flow3.setTarget(userTask2);modelInstance.addFlowElement(flow3);// 添加另一个并行网关用于汇聚ParallelGateway joinGateway = modelInstance.newInstance(ParallelGateway.class);joinGateway.setId("joinGateway");joinGateway.setParallelGatewayType(ParallelGateway.Type.DIVERGING); // 设置为汇聚类型process.addChildElement(joinGateway);// 连接两个用户任务到汇聚网关SequenceFlow flow4 = modelInstance.newInstance(SequenceFlow.class);flow4.setId("flow4");flow4.setSource(userTask1);flow4.setTarget(joinGateway);modelInstance.addFlowElement(flow4);SequenceFlow flow5 = modelInstance.newInstance(SequenceFlow.class);flow5.setId("flow5");flow5.setSource(userTask2);flow5.setTarget(joinGateway);modelInstance.addFlowElement(flow5);// 添加结束事件EndEvent endEvent = modelInstance.newInstance(EndEvent.class);endEvent.setId("endEvent");process.addChildElement(endEvent);// 从汇聚网关到结束事件SequenceFlow flow6 = modelInstance.newInstance(SequenceFlow.class);flow6.setId("flow6");flow6.setSource(joinGateway);flow6.setTarget(endEvent);modelInstance.addFlowElement(flow6);// 部署流程模型RepositoryService repositoryService = /* 获取RepositoryService */;Deployment deployment = repositoryService.createDeployment().addModelInstance("parallelGatewayExample.bpmn", modelInstance).name("Parallel Gateway Example Process").deploy();System.out.println("流程已部署，部署ID: " + deployment.getId());
}
4. 执行与测试
部署完成后，你就可以通过Flowable的RuntimeService启动该流程实例，并通过TaskService处理用户任务了。记得在实际应用中捕获可能的异常，并进行相应的错误处理。
5. 总结
本文介绍了如何使用Java动态创建一个含有并行网关（会签）的Flowable流程模型。通过这种方式，你可以根据业务需求灵活地调整流程结构，而无需预先设计并部署流程定义文件。这极大地增强了系统的适应性和可维护性。实践过程中，还可以进一步探索如何结合表单、变量、监听器等高级特性，以实现更复杂的工作流逻辑。
