// 查询任务
TaskQuery taskQuery = taskService.createTaskQuery();
taskQuery.taskAssignee("testAddExternalTask_admin");
taskQuery.addTaskType(TaskInstanceType.OTHERBPMTASK);
TaskInstance taskInstanceReturn = taskQuery.singleResult();
assertNotNull(taskInstanceReturn);
// 将任务处理者换为testAddExternalTask_test
taskInstanceReturn.setAssignee("testAddExternalTask_test");