Grails select 不返回对象而是返回字符串

Question

如何获取选择标记以返回对象本身而不是字符串？ 每当我创建一个新的 BusinessArea 时，我都会收到一条错误消息:

“无法将类型 java.lang.String 的属性值转换为属性businessType 所需的类型 bassscheduler.BusinessType；嵌套异常为 java.lang.IllegalStateException:无法将类型 [java.lang.String] 的值转换为所需类型[bassscheduler.BusinessType] 属性businessType:找不到匹配的编辑器或转换策略”

我做错了什么吗？我似乎找不到任何关于如何让选择标签返回对象本身而不是字符串的内容

感谢您的帮助

我有以下模型

class BusinessArea {

  BusinessType businessType
  // The date and time this occurence was created
  Date dateCreated
  // The date and time that this occurrence was last maintained.
  Date lastUpdated
  // The identifier for the OPERATOR or PROGRAM that last maintained this occurrence.
  int lastMaintainer
  // The name of the business area
  String name

  static constraints = {
    lastMaintainer blank: false, nullable: false
    name blank: false, nullable: false
  }
}

和 Controller 操作

def createBusinessArea() {

  def businessArea = new BusinessArea(params)
  if (!businessArea.save(flush: true)) {
    render view: "index", model : [businessArea: businessArea, activeTemplate: "businessArea"]
    return 
  }
  redirect controller: "admin", action: "index", model : [activeTemplate: "businessArea"]
}

将此表单提交给 Controller 操作

<g:form controller="admin" action="createBusinessArea"> 
  <div class="row">
    <legend>Business Area</legend>
<div class="span3">
  <label>Business Area:</label>
  <g:textField name="businessArea"/>
</div>
<div class="span3">
  <label>Business Type:</label>
  <g:select name="businessType" from="${businessTypes}" optionValue="name"/>
</div>
  </div>

  <div class="buttons">
    <div class="row">
      <div class="span7" style="padding-top: 2em">
    <g:submitButton class="btn btn-primary pull-right" name="create" value="Create" />
  </div>
    </div>
  </div>
</g:form>

Answer 1

这个:

<g:select name="businessType" from="${businessTypes}" optionValue="name"/>

应该是:

<g:select name="businessType.id" from="${businessTypes}" optionValue="name" optionKey="id" />