/**
   * 开始流程
   *
   * @return
   */
  @RequestMapping(value = "/start.do")
  public String startProcessDefinition(
      HttpServletRequest request,
      @RequestParam("processDefId") String processDefId,
      @RequestParam("userId") String userId) {

    // 用来设置启动流程的人员ID,引擎会自动把用户ID保存到activiti:initiator中
    identityService.setAuthenticatedUserId(userId);

    Map map = new HashMap();
    map.put("owner", userId);
    runtimeService.startProcessInstanceById(processDefId, map);

    return "redirect:/simple/index.do";
  }