[英]Importing and using groovy code in GSP
I am trying to use a groovy function inside a GSP. 我试图在GSP中使用groovy函数。 Please help as I am about to tare my hair out here. 请帮忙,因为我要把头发弄到这里。
At the top of my GSP i have <%@ page import = company.ConstantsFile %>
在我的GSP顶部,我有<%@ page import = company.ConstantsFile %>
Inside my GSP I have 在我的GSP里面我有
<p>
I have been in the heating and cooling business for <%(ConstantsFile.daysBetween())%>
</p>
and my ConstantsFile.groovy 和我的ConstantsFile.groovy
package company
import static java.util.Calendar.*
class ConstantsFile {
def daysBetween() {
def startDate = Calendar.instance
def m = [:]
m[YEAR] = 2004
m[MONTH] = "JUNE"
m[DATE] = 26
startDate.set(m)
def today = Calendar.instance
render today - startDate
}
}
I have also tried changing renter to puts, system.out, etc but that isn't my main problem. 我也尝试将renter更改为puts,system.out等,但这不是我的主要问题。
Error 500: Internal Server Error
URI
/company/
Class
java.lang.NullPointerException
Message
Cannot invoke method daysBetween() on null object
So I try 所以我试试
<p>
I have been in the heating and cooling business for <%(new ConstantsFile.daysBetween())%>
</p>
but then i get 但后来我明白了
Class: org.codehaus.groovy.control.MultipleCompilationErrorsException
unable to resolve class ConstantsFile.daysBetween @ line 37, column 1. (new ConstantsFile.daysBetween()) ^ 1 error
Please someone help me or point me to a website that shows what to do.. I have tried googling and everything talks about ag:select or some other kind of tag... I just want to output the result of the function like I used to in the JSPs. 请有人帮助我或指向一个显示该做什么的网站..我已经尝试了谷歌搜索和一切谈论ag:选择或其他类型的标签...我只想输出像我用过的功能的结果在JSP中。
First, your GSP's import should be: 首先,您的GSP导入应该是:
<%@ page import="company.ConstantsFile" %>
Second, your daysBetween should be static (it makes more sense) and you don't render from anything but a controller: 其次,你的daysBetween应该是静态的(它更有意义)并且你不会从控制器以外的任何东西渲染:
class ConstantsFile {
static daysBetween() {
def startDate = Calendar.instance
def m = [:]
m[YEAR] = 2004
m[MONTH] = "JUNE"
m[DATE] = 26
startDate.set(m)
def today = Calendar.instance
return today - startDate
}
}
Third, access it in the following way: 第三,通过以下方式访问它:
<p>I have been in the heating and cooling business for ${ConstantsFile.daysBetween}</p>
And lastly, you should use a taglib for this. 最后,你应该使用taglib。 I'm editing my post now to add an example 我正在编辑我的帖子以添加一个例子
class MyTagLib {
static namespace = "my"
def daysBetween = { attr ->
out << ConstantsFile.daysBetween()
}
}
Then use in your GSP 然后在您的GSP中使用
<p>I have been in the heating and cooling business for <my:daysBetween /></p>
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