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使用Camunda流程引擎开发,信号启动事件、条件启动事件、消息启...

momory

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2022-03-09 17:17

在使用开源Camunda流程引擎做二次开发时，启动事件是非常有用的，能够帮助我们解决很多的问题。既然能功能那么强大，有哪些启动事件，又能帮我们解决什么问题，以及如何使用呢？

有哪些启动事件？

Camunda 提供了信号启动事件、条件启动事件、消息启动事

解决什么问题？

在实际业务中，如果遇上节点多而且逻辑复杂的流程时，需要启动子流程，这个时候只需要发一个信息或者一个消息、又或者到指定一个条件即可轻松发起子流程。

如何使用呢？

Camunda 已经帮我们做好了API，只需要理解知道怎么使用即可。

流程示例


b9cf49dcd656cd6e13d45122d5fd4c6c.webp 
上面的流程在【自动发起子流程】这个自动服务任务节点，可以帮我们发起下面以3种为开始事件的子流程。9099d597fdd751762d5133b62745a2ce.webpc2bde96f0a163f2d79a712c0899f09b0.webp74cf29ff7a4779b7e61a2548b7a972b8.webp 


主流程的XML文件：

<bpmn2:definitions xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:bpmn2="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:camunda="http://camunda.org/schema/1.0/bpmn" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" xmlns:di="http://www.omg.org/spec/DD/20100524/DI" id="_TZZ5cHYXEeSiaf32_fRHjA" targetNamespace="http://camunda.org/examples" exporter="Camunda Modeler" exporterVersion="4.11.1" xsi:schemaLocation="http://www.omg.org/spec/BPMN/20100524/MODEL BPMN20.xsd">
  <bpmn2:process id="Instantiating_Process" name="测试事件方式发起流程" isExecutable="true">
    <bpmn2:startEvent id="StartEvent_1" name="开始">
      <bpmn2:outgoing>SequenceFlow_1bpmn2:outgoing>
    bpmn2:startEvent>
    <bpmn2:serviceTask id="ServiceTask_1" name="自动发起子流程" camunda:class="com.bpm.config.SignalEventTypeStartProcDelegate">
      <bpmn2:incoming>SequenceFlow_1bpmn2:incoming>
      <bpmn2:outgoing>SequenceFlow_2bpmn2:outgoing>
    bpmn2:serviceTask>
    <bpmn2:sequenceFlow id="SequenceFlow_1" name="" sourceRef="StartEvent_1" targetRef="ServiceTask_1" />
    <bpmn2:userTask id="UserTask_1" name="业务办理" camunda:assignee="demo">
      <bpmn2:incoming>SequenceFlow_2bpmn2:incoming>
      <bpmn2:outgoing>SequenceFlow_3bpmn2:outgoing>
    bpmn2:userTask>
    <bpmn2:sequenceFlow id="SequenceFlow_2" name="" sourceRef="ServiceTask_1" targetRef="UserTask_1" />
    <bpmn2:endEvent id="EndEvent_1" name="结束">
      <bpmn2:incoming>SequenceFlow_3bpmn2:incoming>
    bpmn2:endEvent>
    <bpmn2:sequenceFlow id="SequenceFlow_3" name="" sourceRef="UserTask_1" targetRef="EndEvent_1" />
  bpmn2:process>
  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Instantiating_Process">
      <bpmndi:BPMNEdge id="BPMNEdge_SequenceFlow_3" bpmnElement="SequenceFlow_3" sourceElement="_BPMNShape_UserTask_2" targetElement="_BPMNShape_EndEvent_49">
        <di:waypoint x="554" y="118" />
        <di:waypoint x="662" y="118" />
      bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="BPMNEdge_SequenceFlow_2" bpmnElement="SequenceFlow_2" sourceElement="_BPMNShape_ServiceTask_2" targetElement="_BPMNShape_UserTask_2">
        <di:waypoint x="360" y="118" />
        <di:waypoint x="454" y="118" />
      bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="BPMNEdge_SequenceFlow_1" bpmnElement="SequenceFlow_1" sourceElement="_BPMNShape_StartEvent_13" targetElement="_BPMNShape_ServiceTask_2">
        <di:waypoint x="188" y="118" />
        <di:waypoint x="260" y="118" />
      bpmndi:BPMNEdge>
      <bpmndi:BPMNShape id="_BPMNShape_StartEvent_13" bpmnElement="StartEvent_1">
        <dc:Bounds x="152" y="100" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="159" y="143" width="22" height="14" />
        bpmndi:BPMNLabel>
      bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="_BPMNShape_ServiceTask_2" bpmnElement="ServiceTask_1">
        <dc:Bounds x="260" y="78" width="100" height="80" />
      bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="_BPMNShape_UserTask_2" bpmnElement="UserTask_1">
        <dc:Bounds x="454" y="78" width="100" height="80" />
      bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="_BPMNShape_EndEvent_49" bpmnElement="EndEvent_1">
        <dc:Bounds x="662" y="100" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="670" y="143" width="22" height="14" />
        bpmndi:BPMNLabel>
      bpmndi:BPMNShape>
    bpmndi:BPMNPlane>
  bpmndi:BPMNDiagram>
bpmn2:definitions>

其它3条子流程的XML文件分别是：

<bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" xmlns:di="http://www.omg.org/spec/DD/20100524/DI" xmlns:camunda="http://camunda.org/schema/1.0/bpmn" xmlns:modeler="http://camunda.org/schema/modeler/1.0" id="Definitions_0js57kf" targetNamespace="http://bpmn.io/schema/bpmn" exporter="Camunda Modeler" exporterVersion="4.11.1" modeler:executionPlatform="Camunda Platform" modeler:executionPlatformVersion="7.15.0">
  <bpmn:process id="Process_0qplt59" name="信号事件方式启动流程" isExecutable="true">
    <bpmn:userTask id="Activity_1jhxkz3" name="任务一" camunda:assignee="${assignee}">
      <bpmn:incoming>Flow_0ays4bzbpmn:incoming>
      <bpmn:outgoing>Flow_0vld40obpmn:outgoing>
    bpmn:userTask>
    <bpmn:userTask id="Activity_1d0nrlf" name="任务二" camunda:assignee="${assignee}">
      <bpmn:incoming>Flow_0vld40obpmn:incoming>
      <bpmn:outgoing>Flow_0z13zvfbpmn:outgoing>
    bpmn:userTask>
    <bpmn:endEvent id="Event_1kb0wd1">
      <bpmn:incoming>Flow_0z13zvfbpmn:incoming>
    bpmn:endEvent>
    <bpmn:sequenceFlow id="Flow_0vld40o" sourceRef="Activity_1jhxkz3" targetRef="Activity_1d0nrlf" />
    <bpmn:sequenceFlow id="Flow_0z13zvf" sourceRef="Activity_1d0nrlf" targetRef="Event_1kb0wd1" />
    <bpmn:sequenceFlow id="Flow_0ays4bz" sourceRef="Event_0fltzrj" targetRef="Activity_1jhxkz3" />
    <bpmn:startEvent id="Event_0fltzrj" name="信号启动">
      <bpmn:outgoing>Flow_0ays4bzbpmn:outgoing>
      <bpmn:signalEventDefinition id="SignalEventDefinition_000pg4x" signalRef="Signal_1i2qeo0" />
    bpmn:startEvent>
  bpmn:process>
  <bpmn:signal id="Signal_1i2qeo0" name="signal" />
  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Process_0qplt59">
      <bpmndi:BPMNEdge id="Flow_0ays4bz_di" bpmnElement="Flow_0ays4bz">
        <di:waypoint x="188" y="130" />
        <di:waypoint x="280" y="130" />
      bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_0z13zvf_di" bpmnElement="Flow_0z13zvf">
        <di:waypoint x="550" y="130" />
        <di:waypoint x="632" y="130" />
      bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_0vld40o_di" bpmnElement="Flow_0vld40o">
        <di:waypoint x="380" y="130" />
        <di:waypoint x="450" y="130" />
      bpmndi:BPMNEdge>
      <bpmndi:BPMNShape id="Event_13zdp51_di" bpmnElement="Event_0fltzrj">
        <dc:Bounds x="152" y="112" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="153" y="82" width="44" height="14" />
        bpmndi:BPMNLabel>
      bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Activity_1jhxkz3_di" bpmnElement="Activity_1jhxkz3">
        <dc:Bounds x="280" y="90" width="100" height="80" />
      bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_1kb0wd1_di" bpmnElement="Event_1kb0wd1">
        <dc:Bounds x="632" y="112" width="36" height="36" />
      bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Activity_1d0nrlf_di" bpmnElement="Activity_1d0nrlf">
        <dc:Bounds x="450" y="90" width="100" height="80" />
      bpmndi:BPMNShape>
    bpmndi:BPMNPlane>
  bpmndi:BPMNDiagram>
bpmn:definitions>



<bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:di="http://www.omg.org/spec/DD/20100524/DI" xmlns:modeler="http://camunda.org/schema/modeler/1.0" id="Definitions_1gofk0s" targetNamespace="http://bpmn.io/schema/bpmn" exporter="Camunda Modeler" exporterVersion="4.11.1" modeler:executionPlatform="Camunda Platform" modeler:executionPlatformVersion="7.15.0">
  <bpmn:process id="Process_1gnunqx" name="条件事件方式启动流程" isExecutable="true">
    <bpmn:startEvent id="StartEvent_1" name="条件启动">
      <bpmn:outgoing>Flow_06zvpffbpmn:outgoing>
      <bpmn:conditionalEventDefinition id="ConditionalEventDefinition_11cu5dx">
        <bpmn:condition xsi:type="bpmn:tFormalExpression">${isStart==true}bpmn:condition>
      bpmn:conditionalEventDefinition>
    bpmn:startEvent>
    <bpmn:endEvent id="Event_1bw20g9">
      <bpmn:incoming>Flow_1vmm5tjbpmn:incoming>
    bpmn:endEvent>
    <bpmn:userTask id="Activity_0sc060o" name="条件方式，任务一">
      <bpmn:incoming>Flow_06zvpffbpmn:incoming>
      <bpmn:outgoing>Flow_1vmm5tjbpmn:outgoing>
    bpmn:userTask>
    <bpmn:sequenceFlow id="Flow_1vmm5tj" sourceRef="Activity_0sc060o" targetRef="Event_1bw20g9" />
    <bpmn:sequenceFlow id="Flow_06zvpff" sourceRef="StartEvent_1" targetRef="Activity_0sc060o" />
  bpmn:process>
  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Process_1gnunqx">
      <bpmndi:BPMNEdge id="Flow_1vmm5tj_di" bpmnElement="Flow_1vmm5tj">
        <di:waypoint x="390" y="117" />
        <di:waypoint x="492" y="117" />
      bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_06zvpff_di" bpmnElement="Flow_06zvpff">
        <di:waypoint x="188" y="117" />
        <di:waypoint x="290" y="117" />
      bpmndi:BPMNEdge>
      <bpmndi:BPMNShape id="Event_1slknve_di" bpmnElement="StartEvent_1">
        <dc:Bounds x="152" y="99" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="148" y="142" width="44" height="14" />
        bpmndi:BPMNLabel>
      bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_1bw20g9_di" bpmnElement="Event_1bw20g9">
        <dc:Bounds x="492" y="99" width="36" height="36" />
      bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Activity_16yxguf_di" bpmnElement="Activity_0sc060o">
        <dc:Bounds x="290" y="77" width="100" height="80" />
      bpmndi:BPMNShape>
    bpmndi:BPMNPlane>
  bpmndi:BPMNDiagram>
bpmn:definitions>


<bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:camunda="http://camunda.org/schema/1.0/bpmn" xmlns:di="http://www.omg.org/spec/DD/20100524/DI" xmlns:modeler="http://camunda.org/schema/modeler/1.0" id="Definitions_1uxobnf" targetNamespace="http://bpmn.io/schema/bpmn" exporter="Camunda Modeler" exporterVersion="4.11.1" modeler:executionPlatform="Camunda Platform" modeler:executionPlatformVersion="7.15.0">
  <bpmn:process id="Process_0av3mad" name="消息事件方式发起流程" isExecutable="true">
    <bpmn:userTask id="Activity_0amzx6i" name="经理审批" camunda:assignee="demo">
      <bpmn:incoming>Flow_055trdzbpmn:incoming>
      <bpmn:outgoing>Flow_16yqwjtbpmn:outgoing>
    bpmn:userTask>
    <bpmn:sequenceFlow id="Flow_055trdz" sourceRef="StartEvent_1" targetRef="Activity_0amzx6i" />
    <bpmn:userTask id="Activity_0ipk02z" name="财务审批" camunda:assignee="demo">
      <bpmn:incoming>Flow_16yqwjtbpmn:incoming>
      <bpmn:outgoing>Flow_0lwwz4nbpmn:outgoing>
    bpmn:userTask>
    <bpmn:sequenceFlow id="Flow_16yqwjt" sourceRef="Activity_0amzx6i" targetRef="Activity_0ipk02z" />
    <bpmn:endEvent id="Event_03yf0hk">
      <bpmn:incoming>Flow_0lwwz4nbpmn:incoming>
    bpmn:endEvent>
    <bpmn:sequenceFlow id="Flow_0lwwz4n" sourceRef="Activity_0ipk02z" targetRef="Event_03yf0hk" />
    <bpmn:startEvent id="StartEvent_1" name="消息">
      <bpmn:outgoing>Flow_055trdzbpmn:outgoing>
      <bpmn:messageEventDefinition id="MessageEventDefinition_0o0ivuo" messageRef="Message_1i854ob" />
    bpmn:startEvent>
  bpmn:process>
  <bpmn:message id="Message_1i854ob" name="telMessage" />
  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Process_0av3mad">
      <bpmndi:BPMNEdge id="Flow_0lwwz4n_di" bpmnElement="Flow_0lwwz4n">
        <di:waypoint x="630" y="117" />
        <di:waypoint x="702" y="117" />
      bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_16yqwjt_di" bpmnElement="Flow_16yqwjt">
        <di:waypoint x="400" y="117" />
        <di:waypoint x="530" y="117" />
      bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_055trdz_di" bpmnElement="Flow_055trdz">
        <di:waypoint x="215" y="117" />
        <di:waypoint x="300" y="117" />
      bpmndi:BPMNEdge>
      <bpmndi:BPMNShape id="Activity_0amzx6i_di" bpmnElement="Activity_0amzx6i">
        <dc:Bounds x="300" y="77" width="100" height="80" />
      bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Activity_0ipk02z_di" bpmnElement="Activity_0ipk02z">
        <dc:Bounds x="530" y="77" width="100" height="80" />
      bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_03yf0hk_di" bpmnElement="Event_03yf0hk">
        <dc:Bounds x="702" y="99" width="36" height="36" />
      bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_0kfrdnl_di" bpmnElement="StartEvent_1">
        <dc:Bounds x="179" y="99" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="186" y="142" width="22" height="14" />
        bpmndi:BPMNLabel>
      bpmndi:BPMNShape>
    bpmndi:BPMNPlane>
  bpmndi:BPMNDiagram>
bpmn:definitions>



画流程还是很简单的，主要还是不同的子流程需配制不同的参数。8700df84e567fb02e4738b9ddce0e85d.webp7f1221447a97a4ce01ea045a6d56d27a.webp219ed8da53ebc1229fa378a2579d7438.webp

部署流程验证测试110fa3a05e4a9746203b5a830ceff3af.webp 现在要做的是启动【测试事件方式发起流程】这条流程，流程发起后会帮助发起其它子流程。依次来，先发帮助发起信号事件子流程：b2d49928bb7c57f0173ffec55339912e.webp
点Start后，在【信号事件方式启动流程】的流程中产生了第一个节点任务【任务一】：
2edaae889e25c2474e99fb41043028d2.webp317feda2534e45f26d950505ef3be429.webp2f6dd274a60bd28c3048c2657b8af299.webpbdae40f68d2064c82cb2a206114262e5.webp0be4e3b369dbc4f4dab31affe139655d.webp
都能够通过事件方式发起流程，并产生流程中第一个用户任务。在主流程程中，通过自动任务的试去发起流程，相关代码如下：
package com.bpm.config;

import lombok.extern.slf4j.Slf4j;import org.apache.commons.lang3.ObjectUtils;import org.camunda.bpm.engine.RuntimeService;import org.camunda.bpm.engine.delegate.DelegateExecution;import org.camunda.bpm.engine.delegate.JavaDelegate;import java.util.HashMap;import java.util.Map;

/*** 消息启动子流程* 信号启动子流程* 条件启动子流程*/
@Slf4jpublic class SignalEventTypeStartProcDelegate implements JavaDelegate {    @Override    public void execute(DelegateExecution execution) throws Exception {        try {
            Object type =  execution.getVariable("type");            if(ObjectUtils.isEmpty(type)){                log.debug("启动事件方式启动流程，没有设置事件的类型，参数【type】为空");            }

            Object obj = execution.getVariable("parameter");            if(ObjectUtils.isEmpty(obj)){                log.error("启动流程，参数【parameter】为必须参数，不能为空");                return;            }

            RuntimeService runtimeService = execution.getProcessEngineServices().getRuntimeService();            switch (type.toString()) {                case "message": // 消息方式                    runtimeService.startProcessInstanceByMessage(obj.toString(), execution.getVariables());                    break;                case "sign": // 信号方式                    runtimeService.createSignalEvent(obj.toString()).setVariables(execution.getVariables()).send();                    break;                case "conditional": // 条件方式
                    Map<String, Object> map = new HashMap<>();
                    map.put(obj.toString(), Boolean.TRUE);
                    map.putAll(execution.getVariables());
//                    List instanceList =
                    runtimeService.createConditionEvaluation().setVariables(map).evaluateStartConditions();
                    break;
                default: // 默认无事件方式启动流程
                    runtimeService.startProcessInstanceByKey(obj.toString());
                    break;
            }
            //// to do
            // 如果需要回写启动的流程实例ID，可以用事件的方式去启动
        }catch (Exception e){
            throw new Exception("启动流程异常：{}", e);
        }
    }
}
OK，关于事件方式启动流程就写到定里。
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