Flowable 实现【选择下一步流程审核人】

原理：

1. 在流程表单数据正式提交审核前，将流程表单数据 formData 及流程执行实例 ExecutionEntity 传递给接口
2. 接口在流程定义取得当前节点信息并循环查找出线 SequenceFlow 还需要注意遇到网关时应该怎样处理
3. 使用变量执行出线 SequenceFlow 条件（类似完成提交任务操作）
4. 找出第一个用户任务UserTask 根据这个UserTask中信息，我们就能拿到流程审核人了
5. 最重要的一点，在第三点中使用变量去执行条件的时候，变量会被持久化至数据库中，所以我们一定要在事务中进行操作，操作完成后回滚清空当前事务，避免数据紊乱

项目完整源码链接

以下是全部代码，此逻辑仅供参考

1package com.nutzfw.core.plugin.flowable.cmd;
2
3import org.apache.commons.collections.CollectionUtils;
4import org.flowable.bpmn.model.*;
5import org.flowable.common.engine.impl.interceptor.Command;
6import org.flowable.common.engine.impl.interceptor.CommandContext;
7import org.flowable.engine.impl.persistence.entity.ExecutionEntity;
8import org.flowable.engine.impl.util.condition.ConditionUtil;
9
10import java.util.List;
11import java.util.Map;
12
13/**
14 * @author huchuc@vip.qq.com
15 * @date: 2019/7/9
16 * 使用示例，一定要放到事务中，否则变量会入库，导致数据紊乱
17 * try {
18 * Trans.begin();
19 * UserTask userTask = managementService.executeCommand(new FindNextUserTaskNodeCmd(execution, bpmnModel, vars));
20 * System.out.println(userTask.getId());
21 * } finally {
22 * Trans.clear(true);
23 * }
24 */
25public class FindNextUserTaskNodeCmd implements Command<UserTask> {
26
27    private final ExecutionEntity execution;
28    private final BpmnModel bpmnModel;
29    private Map<String, Object> vars;
30    /**
31     * 返回下一用户节点
32     */
33    private UserTask nextUserTask;
34
35    /**
36     * @param execution 当前执行实例
37     * @param bpmnModel 当前执行实例的模型
38     * @param vars      参与计算流程条件的变量
39     */
40    public FindNextUserTaskNodeCmd(ExecutionEntity execution, BpmnModel bpmnModel, Map<String, Object> vars) {
41        this.execution = execution;
42        this.bpmnModel = bpmnModel;
43        this.vars = vars;
44    }
45
46    /**
47     * @param execution 当前执行实例
48     * @param bpmnModel 当前执行实例的模型
49     */
50    public FindNextUserTaskNodeCmd(ExecutionEntity execution, BpmnModel bpmnModel) {
51        this.execution = execution;
52        this.bpmnModel = bpmnModel;
53    }
54
55    @Override
56    public UserTask execute(CommandContext commandContext) {
57        execution.setVariables(vars);
58        FlowElement currentNode = bpmnModel.getFlowElement(execution.getActivityId());
59        List<SequenceFlow> outgoingFlows = ((FlowNode) currentNode).getOutgoingFlows();
60        if (CollectionUtils.isNotEmpty(outgoingFlows)) {
61            this.findNextUserTaskNode(outgoingFlows, execution);
62        }
63        return nextUserTask;
64    }
65
66
67    void findNextUserTaskNode(List<SequenceFlow> outgoingFlows, ExecutionEntity execution) {
68        sw:
69        for (SequenceFlow outgoingFlow : outgoingFlows) {
70            if (ConditionUtil.hasTrueCondition(outgoingFlow, execution)) {
71                if (outgoingFlow.getTargetFlowElement() instanceof ExclusiveGateway) {
72                    //只有排他网关才继续
73                    ExclusiveGateway exclusiveGateway = (ExclusiveGateway) outgoingFlow.getTargetFlowElement();
74                    findNextUserTaskNode(exclusiveGateway.getOutgoingFlows(), execution);
75                } else if (outgoingFlow.getTargetFlowElement() instanceof UserTask) {
76                    nextUserTask = (UserTask) outgoingFlow.getTargetFlowElement();
77                    //找到第一个符合条件的userTask就跳出循环
78                    break sw;
79                }
80            }
81        }
82    }
83}