在实际的业务中，可能存在存在这么一种情况，当流程运行到某一个环节时，可能需要同时多个人的参与，才可以完成此环节。此时就可以用到activiti的多实例来解决此问题。
一、将一个节点设置成多实例的方法：
要把一个节点设置为多实例，节点xml元素必须设置一个multiInstanceLoopCharacteristics子元素。
当isSequential=true时，表示的顺序执行，即虽然该节点有多条任务，但只有上一条执行完，才可以执行下一条。
当isSequential=false时，表示的并行执行，即该节点下的多条任务可以同时执行。
二、设置会签环节的参与者：
activiti:collection：用于执行该会签环节的参与参与的人，此处是使用的一个名叫pers的流程变量
activiti:elementVariable：此处表示的是每一个分支都有一个名叫per的流程变量，和上方的activiti:assignee结合使用就可以执行该分支应该由谁来处理。
三.指定会签环节的结束条件：
当画红线的部分返回一个true的时候，该会签环节结束。进入下一个流程执行的环节.
completionCondition中写的是juel表达式。其中的mulitiInstance如果是和spring整合了，就是spring管理的bean的id，否则就是流程变量的key.
四、会签环节中涉及的几个默认的流程变量
1.nrOfInstances 该会签环节中总共有多少个实例
2.nrOfActiveInstances 当前活动的实例的数量，即还没有 完成的实例数量。
3.nrOfCompletedInstances 已经完成的实例的数量
五、代码如下：
1.分配会签环节的人：
/**
* 分配下一环节会签的人
*
* @author huan
*
*/
public class AssgineeMultiInstancePer implements JavaDelegate {
@Override
public void execute(DelegateExecution execution) throws Exception {
System.out.println("设置会签环节的人员.");
execution.setVariable("pers", Arrays.asList("张三", "李四", "王五", "赵六"));
}
}
2.多实例判断完成的条件：（注意：有于我没有和spring整合，所以此类要实现Serializable接口）
/**
* 多实例完成的条件判断
* @author huan
*/
public class MulitiInstanceCompleteTask implements Serializable {
private static final long serialVersionUID = 1L;
public boolean completeTask(DelegateExecution execution) {
System.out.println("总的会签任务数量：" + execution.getVariable("nrOfInstances") + "当前获取的会签任务数量：" + execution.getVariable("nrOfActiveInstances") + " - " + "已经完成的会签任务数量：" + execution.getVariable("nrOfCompletedInstances"));
System.out.println("I am invoked.");
return false;
}
}
3.会签环节中的一个监听器：
/**
* 测试会签过程中监听器的执行情况
* @author huan
*/
public class TestLinstener implements TaskListener {
private static final long serialVersionUID = -5754522101489239675L;
@Override
public void notify(DelegateTask delegateTask) {
System.out.print(delegateTask.getId() + " - " + delegateTask.getProcessInstanceId() + " - " + delegateTask.getEventName() + " - " + delegateTask.getTaskDefinitionKey());
}
}
4.测试代码：
/**
* 测试会签
* @author huan
*/
public class TestMultiInstance {
@Test
public void testProcess() {
ProcessEngine processEngine = ProcessEngines.getDefaultProcessEngine();
RepositoryService repositoryService = processEngine.getRepositoryService();
RuntimeService runtimeService = processEngine.getRuntimeService();
TaskService taskService = processEngine.getTaskService();
Deployment deploy = repositoryService.createDeployment()//
.name("会签流程测试")//
.addInputStream("multiInstances.bpmn", this.getClass().getResourceAsStream("multiInstances.bpmn"))//
.addInputStream("multiInstances.png", this.getClass().getResourceAsStream("multiInstances.png"))//
.deploy();
System.out.println(deploy.getId() + " " + deploy.getName());
Map<String, Object> variables = new HashMap<String, Object>();
variables.put("mulitiInstance", new MulitiInstanceCompleteTask());
ProcessInstance pi = runtimeService.startProcessInstanceByKey("multiInstances",variables);
System.out.println(pi.getId() + " " + pi.getActivityId());
Task task1 = taskService.createTaskQuery().processInstanceId(pi.getId()).taskAssignee("张三").singleResult();
System.out.println(task1.getId() + " - " + task1.getAssignee() + " - " + task1.getProcessInstanceId() + " - " + task1.getProcessDefinitionId());
Task task2 = taskService.createTaskQuery().processInstanceId(pi.getId()).taskAssignee("李四").singleResult();
System.out.println(task2.getId() + " - " + task2.getAssignee() + " - " + task2.getProcessInstanceId() + " - " + task2.getProcessDefinitionId());
Task task3 = taskService.createTaskQuery().processInstanceId(pi.getId()).taskAssignee("王五").singleResult();
System.out.println(task3.getId() + " - " + task3.getAssignee() + " - " + task3.getProcessInstanceId() + " - " + task3.getProcessDefinitionId());
Task task4 = taskService.createTaskQuery().processInstanceId(pi.getId()).taskAssignee("赵六").singleResult();
if (task4 != null) {
System.out.println(task4.getId() + " - " + task4.getAssignee() + " - " + task4.getProcessInstanceId() + " - " + task4.getProcessDefinitionId());
}
Task task5 = taskService.createTaskQuery().processInstanceId(pi.getId()).taskAssignee("钱七").singleResult();
System.out.println(task5);
taskService.complete(task1.getId());
taskService.complete(task2.getId());
taskService.complete(task3.getId());
Task task6 = taskService.createTaskQuery().processInstanceId(pi.getId()).taskAssignee("钱七").singleResult();
System.out.println(task6);
taskService.complete(task4.getId());
Task task7 = taskService.createTaskQuery().processInstanceId(pi.getId()).taskAssignee("钱七").singleResult();
System.out.println(task7);
taskService.complete(task7.getId());
ProcessInstance processInstance = runtimeService.createProcessInstanceQuery().processInstanceId(pi.getId()).singleResult();
if (null == processInstance) {
System.out.println("流程完成.");
}
}
}
5.流程文件：
<?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="multiInstances" name="流程会签测试" isExecutable="true">
<startEvent id="startevent1" name="Start"></startEvent>
<sequenceFlow id="flow1" sourceRef="startevent1" targetRef="A001"></sequenceFlow>
<serviceTask id="A001" name="设置下一环节的人" activiti:class="com.huan.activiti.liuyang.会签.AssgineeMultiInstancePer"></serviceTask>
<userTask id="B001" name="会签环节" activiti:assignee="${per}">
<extensionElements>
<activiti:taskListener event="complete" class="com.huan.activiti.liuyang.会签.TestLinstener"></activiti:taskListener>
</extensionElements>
<multiInstanceLoopCharacteristics isSequential="false" activiti:collection="pers" activiti:elementVariable="per">
<completionCondition>${mulitiInstance.completeTask(execution)}</completionCondition>
</multiInstanceLoopCharacteristics>
</userTask>
<sequenceFlow id="flow2" sourceRef="A001" targetRef="B001"></sequenceFlow>
<userTask id="C001" name="会签后的环节" activiti:assignee="钱七"></userTask>
<sequenceFlow id="flow3" sourceRef="B001" targetRef="C001"></sequenceFlow>
<endEvent id="endevent1" name="End"></endEvent>
<sequenceFlow id="flow4" sourceRef="C001" targetRef="endevent1"></sequenceFlow>
</process>
<bpmndi:BPMNDiagram id="BPMNDiagram_multiInstances">
<bpmndi:BPMNPlane bpmnElement="multiInstances" id="BPMNPlane_multiInstances">
<bpmndi:BPMNShape bpmnElement="startevent1" id="BPMNShape_startevent1">
<omgdc:Bounds height="35.0" width="35.0" x="100.0" y="240.0"></omgdc:Bounds>
</bpmndi:BPMNShape>
<bpmndi:BPMNShape bpmnElement="A001" id="BPMNShape_A001">
<omgdc:Bounds height="71.0" width="117.0" x="190.0" y="222.0"></omgdc:Bounds>
</bpmndi:BPMNShape>
<bpmndi:BPMNShape bpmnElement="B001" id="BPMNShape_B001">
<omgdc:Bounds height="55.0" width="105.0" x="380.0" y="230.0"></omgdc:Bounds>
</bpmndi:BPMNShape>
<bpmndi:BPMNShape bpmnElement="C001" id="BPMNShape_C001">
<omgdc:Bounds height="55.0" width="105.0" x="561.0" y="230.0"></omgdc:Bounds>
</bpmndi:BPMNShape>
<bpmndi:BPMNShape bpmnElement="endevent1" id="BPMNShape_endevent1">
<omgdc:Bounds height="35.0" width="35.0" x="740.0" y="240.0"></omgdc:Bounds>
</bpmndi:BPMNShape>
<bpmndi:BPMNEdge bpmnElement="flow1" id="BPMNEdge_flow1">
<omgdi:waypoint x="135.0" y="257.0"></omgdi:waypoint>
<omgdi:waypoint x="190.0" y="257.0"></omgdi:waypoint>
</bpmndi:BPMNEdge>
<bpmndi:BPMNEdge bpmnElement="flow2" id="BPMNEdge_flow2">
<omgdi:waypoint x="307.0" y="257.0"></omgdi:waypoint>
<omgdi:waypoint x="380.0" y="257.0"></omgdi:waypoint>
</bpmndi:BPMNEdge>
<bpmndi:BPMNEdge bpmnElement="flow3" id="BPMNEdge_flow3">
<omgdi:waypoint x="485.0" y="257.0"></omgdi:waypoint>
<omgdi:waypoint x="561.0" y="257.0"></omgdi:waypoint>
</bpmndi:BPMNEdge>
<bpmndi:BPMNEdge bpmnElement="flow4" id="BPMNEdge_flow4">
<omgdi:waypoint x="666.0" y="257.0"></omgdi:waypoint>
<omgdi:waypoint x="740.0" y="257.0"></omgdi:waypoint>
</bpmndi:BPMNEdge>
</bpmndi:BPMNPlane>
</bpmndi:BPMNDiagram>
</definitions>
7.流程图：
如若那个地方写的不对，欢迎指出。