Unable to render date from model template

问题

I'm working on a Grails project with Freemarker and am having trouble rendering a date from the data model. I start put placing a date into the model

def dataModel = [:]
def dataDate = new Date().parse("yyyy-MM-dd","2015-08-20")
dataModel.put("someDate",dataDate)

I then loop through the dataModel to verify the data types

dataModel.each { name, value ->
    println "${name} : ${value} (Value is type: ${value.getClass()})"
}

For this my output is: someDate : Thu Aug 20 00:00:00 CDT 2015 (Value is type: class java.util.Date)

Next I set up my confiuration and try to process the template

Configuration cfg = new Configuration(Configuration.VERSION_2_3_22)
cfg.setDefaultEncoding("UTF-8")
def ftlTemplate = new Template("name", new StringReader("${someDate}"), cfg)
Writer out = new StringWriter()
ftlTemplate.process(dataModel, out)
output = out.toString()

At this point I receive the following error

ERROR freemarker.runtime  - Error executing FreeMarker template
Message: Can't convert the date-like value to string because it isn't known if it's a date (no time part), time or date-time value.
The blamed expression:
==> someDate  [in template "name" at line 1, column 3]

I've found a Freemarker engine online here: http://freemarker-online.kenshoo.com/ and if I run the same datamodel and template through that the ouput I receive is: Aug 20, 2015

Can anyone point out where I am going wrong? I would like to render the output like that online engine does.

Thanks

回答1:

The problem is (as the error message states) is that it's technically impossible to decide in general, if a java.util.Date stands for a date-only, date-time or time-only value. This is a technical fact that's outside FreeMarker. FreeMarker offers these ways to handle this problem:

Use ?date, ?time and ?datetime operators to give FreeMarker a hint in the template. See: http://freemarker.org/docs/ref_builtins_date.html#ref_builtin_date_datetype
Use java.sql.Date and java.sql.Timestamp and java.sql.Timestamp, where there's no such ambiguity. (Beware with Timestamp's funny fraction second handling though.)
Wrap the values manually into TemplateDateModel, where you can specify which kind of value it is. Then drop the TemplateDateModel into the data-model.

回答2:

Change

new StringReader("${someDate}")

new StringReader('${someDate}')

The double quotes are probably causing double tempering

回答3:

hi,look! you can try like these:

<td name="">${value.startTime?string('dd.MM.yyyy HH:mm:ss')}</td>

the you can replace value.startTime with the target varibale which is date or timestamp type

来源：https://stackoverflow.com/questions/32123950/unable-to-render-date-from-model-template

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groovy

freemarker