Nullable date in Freemarker

This is a piece of my freemarker template:

${order.needByDate?if_exists?date}

I want it to work as following:

• if needByDate is null, then write nothing
• if it is not null, then write the date part

The above works only in second scenario. What is the 开发者_如何学编程correct way to achieve this?

This should also work

${(order.needByDate?date)!}

The parentheses are necessary

You can also add a default value such as "n/a" like this

${(order.needByDate?date)!"n/a"}

There may be a smarter way of doing this but the following should do the job.

<#if order.needByDate??>${order.needByDate?date}</#if>

A solution that considers null and empty-string values:

For Freemarker version 2.3.23 or newer:

${aDateField?has_content?then(aDateField?datetime?string["MM/dd/yyyy hh:mm:ss"],"")}

For older versions:

<#if aDateField?has_content>
${aDateField?datetime?string["MM/dd/yyyy hh:mm:ss"]}
</#if>

You can test it at https://try.freemarker.apache.org/