grails - Grails:从gsp调用Domain方法

Question

我有以下域类:

package com.example

class Location {
   String state

    def getStatesList(){

    def states = ['AL','AK','AZ','AR','CA','CO','CT',
         'DC','DE','FL','GA','HI','ID','IL','IN','IA',
         'KS','KY','LA','ME','MD','MA','MI','MN','MS',
         'MO','MT','NE','NV','NH','NJ','NM','NY','NC',
         'ND','OH','OK','OR','PA','RI','SC','SD','TN',
         'TX','UT','VT','VA','WA','WV','WI','WY']
    return states
   }
} 

在我的gsp中，我试图像这样在选择下拉列表中显示状态列表

<g:select name="location.state" class="form-control" from="${com.example.Location?.getStatesList()}" value="${itemInstance?.location?.state}" noSelection="['': '']" />

这样，我收到“缺少方法异常”

如果我使用list更改方法，我将不再收到错误，但我不希望这样。

from="${com.example.Location?.list()}"    // works
from="${com.example.Location?.getStatesList()}"     // does not work

任何帮助是极大的赞赏。

Answer 1

正如dmahaptro所说，您可以通过将getStatesList()设为静态方法来纠正此问题。

class Location {
   String state

   static List<String> getStatesList() {
         ['AL','AK','AZ','AR','CA','CO','CT',
         'DC','DE','FL','GA','HI','ID','IL','IN','IA',
         'KS','KY','LA','ME','MD','MA','MI','MN','MS',
         'MO','MT','NE','NV','NH','NJ','NM','NY','NC',
         'ND','OH','OK','OR','PA','RI','SC','SD','TN',
         'TX','UT','VT','VA','WA','WV','WI','WY']
   }
} 

然后，您将能够执行Location.statesList或Location.getStatesList()。

另类

我认为更干净的替代方法是使用最终常量:

class Location {
   String state

   static final List<String> STATES =
         ['AL','AK','AZ','AR','CA','CO','CT',
         'DC','DE','FL','GA','HI','ID','IL','IN','IA',
         'KS','KY','LA','ME','MD','MA','MI','MN','MS',
         'MO','MT','NE','NV','NH','NJ','NM','NY','NC',
         'ND','OH','OK','OR','PA','RI','SC','SD','TN',
         'TX','UT','VT','VA','WA','WV','WI','WY']
} 

然后，您可以使用相同的方式访问列表:Location.STATES。区别在于，全大写字母名称表示一个不变的值(并且不需要访问数据库)。