grails - Groovy / Grails：从列表创建地图

Question

我有两个清单：

 def courseList  = PublicTraining.executeQuery(
     "SELECT t.course.id, t.course.name from PublicTraining AS t")
 def cityList  = PublicTraining.executeQuery(
     "SELECT t.venue.city.id, t.venue.city.name from PublicTraining AS t")

和：

courseList  = [[1, weblogic], [2, ajax]]
cityList   = [[1, City1], [2, City2]]

我怎样才能创建一个Map看起来像这样的？

resultMap = ['Course':[['1', 'weblogic'],['2', 'ajax']], 'City':[['1','City1'],
    ['2','City2']] ]