public void revoke(String objId) throws Exception {

Task task = taskService.createTaskQuery().processInstanceBusinessKey(objId).singleResult();

if(task==null) {

throw new ServiceException("流程未启动或已执行完成，无法撤回");

}

LoginUser loginUser = SessionContext.getLoginUser();

List htiList = historyService.createHistoricTaskInstanceQuery()

.processInstanceBusinessKey(objId)

.orderByTaskCreateTime()

.asc()

.list();

String myTaskId = null;

HistoricTaskInstance myTask = null;

for(HistoricTaskInstance hti : htiList) {

if(loginUser.getUsername().equals(hti.getAssignee())) {

myTaskId = hti.getId();

myTask = hti;

break;

}

}

if(null==myTaskId) {

throw new ServiceException("该任务非当前用户提交，无法撤回");

}

String processDefinitionId = myTask.getProcessDefinitionId();

ProcessDefinitionEntity processDefinitionEntity = (ProcessDefinitionEntity) repositoryService.createProcessDefinitionQuery().processDefinitionId(processDefinitionId).singleResult();

BpmnModel bpmnModel = repositoryService.getBpmnModel(processDefinitionId);

//变量

//Map variables = runtimeService.getVariableInstances(currentTask.getExecutionId());

String myActivityId = null;

List haiList = historyService.createHistoricActivityInstanceQuery()

.executionId(myTask.getExecutionId()).finished().list();

for(HistoricActivityInstance hai : haiList) {

if(myTaskId.equals(hai.getTaskId())) {

myActivityId = hai.getActivityId();

break;

}

}

FlowNode myFlowNode = (FlowNode) bpmnModel.getMainProcess().getFlowElement(myActivityId);

Execution execution = runtimeService.createExecutionQuery().executionId(task.getExecutionId()).singleResult();

String activityId = execution.getActivityId();

logger.warn("------->> activityId:" + activityId);

FlowNode flowNode = (FlowNode) bpmnModel.getMainProcess().getFlowElement(activityId);

//记录原活动方向

List oriSequenceFlows = new ArrayList();

oriSequenceFlows.addAll(flowNode.getOutgoingFlows());

//清理活动方向

flowNode.getOutgoingFlows().clear();

//建立新方向

List newSequenceFlowList = new ArrayList();

SequenceFlow newSequenceFlow = new SequenceFlow();

newSequenceFlow.setId("newSequenceFlowId");

newSequenceFlow.setSourceFlowElement(flowNode);

newSequenceFlow.setTargetFlowElement(myFlowNode);

newSequenceFlowList.add(newSequenceFlow);

flowNode.setOutgoingFlows(newSequenceFlowList);

Authentication.setAuthenticatedUserId(loginUser.getUsername());

taskService.addComment(task.getId(), task.getProcessInstanceId(), "撤回");

Map currentVariables = new HashMap();

currentVariables.put("applier", loginUser.getUsername());

//完成任务

taskService.complete(task.getId(),currentVariables);

//恢复原方向

flowNode.setOutgoingFlows(oriSequenceFlows);

}

https://blog.csdn.net/yongboyhood/article/details/70833021