JBPM4.3 怎么获得历史任务的activityName？

我用historyService.createHistoryTaskQuery().executionId(executionId); 查出流程的所有历史任务。
怎么查每个任务的activityName啊？API HistoryActivityInstanceQuery 里好像没提供相应的方法？

[quote]为什么我 historyTask.getOutcome();得到的都是“jbpm_no_task_outcome_specified_jbpm”这个字符串阿？[/quote]
[b][color=blue]jbpm_no_task_outcome_specified_jbpm 说明流转路径是默认的流转路径, 你可以通过获得ProcessDefinition , 再获得该节点的默认路径的.[/color][/b]
[code="java"]
// 这里是代码片段, 不是完整的
Map map = processDefinition.getActivitiesMap();

String activityName = activityInstance.getActivityName();
String transitionName = hai.getTransitionName();

if (transitionName == null || transitionName.length() == 0
|| Task.STATE_COMPLETED.equals(transitionName)
|| TaskConstants.NO_TASK_OUTCOME_SPECIFIED.equals(transitionName)) {
transitionName = "";
Activity activity = map.get(activityName); // 得到Activity
if (activity != null) { // 下面是得到默认的transitionName
Transition transition = activity.getDefaultOutgoingTransition();
if (transition == null && (activity.getOutgoingTransitions() != null)
&& (activity.getOutgoingTransitions().size() == 1)) {
transition = activity.getOutgoingTransitions().get(0);
}
if (transition != null) {
transitionName = transition.getName();
}
}
}
[/code]

[quote]还有task和 Activity 到底有什么区别呀？ [/quote]
[color=blue][b]task相当于Activity 的子集, Activity包含task[/b][/color]

[code="java"]
// 好像只能自己写hql了
HistoryTaskInstanceImpl hti =
getHistoryTaskInstanceByTaskId(historyTask.getId());
System.out.println(hti.getActivityName());

public HistoryTaskInstanceImpl getHistoryTaskInstanceByTaskId(final String taskId){
return processEngine.execute(new Command(){
private static final long serialVersionUID = 1L;
@Override
public HistoryTaskInstanceImpl execute(Environment environment)
throws Exception {
Session session = environment.get(Session.class);
StringBuilder hql = new StringBuilder();
hql.append("select hti from ").append(HistoryTaskInstanceImpl.class.getName());
hql.append(" as hti ");
hql.append("where hti.historyTask.dbid = :taskDbid");
return (HistoryTaskInstanceImpl) session.createQuery(hql.toString())
.setLong("taskDbid", Long.valueOf(taskId)).uniqueResult();
}
});
}
[/code]