There should be one-- and preferably only one --obvious way to do it.

freemarker-howto.md

${.version}  当前 freemarker 的版本
${.locale?lower_case?replace("_", "-")}  当前 Locale，例 en-us

${userName!"John"}  为空的时候不报错，给一个默认值

freemarker-debugger

<#import "debugger.ftl" as debugger />
<@debugger.debug depth=3 />
<@debugger.debugDynamic />

freemarker-commons

freemarker-json

<#import "json.ftl" as json>
<script>
var model = <@json.stringify your_model_here />;
</script>

spring.ftl, examples

auto append ;jsessionid bug

Directive

1. Directives
2. Defining your own directives

Related Articles

1. Official FAQ
2. Introduction to FreeMarker Template (FTL)