Freemarker Alternative (square bracket) syntax

Note:

This feature exists since FreeMarker 2.3.4.

FreeMarker supports an alternative syntax, where [ and ] is used instead of < and > in FreeMarker directives and comments, for example:

• Calling predefined directive: [#list animals as animal]...[/#list]

• Calling user-defined directive: [@myMacro /]

• Comment: [#-- the comment --]

To use the alternative syntax instead of the default one, start the template with the ftl directive using the alternative syntax. If you don't know what is the ftl directive, just start the template with [#ftl], and remember that it should be the very first thing in the file (except thatwhite-space can precede it). For example, this is how the last example of the Getting Started looks with the alternative syntax (assuming it's a complete template, not just a fragment):

[#ftl]<p>We have these animals:
<table border=1>
  <tr><th>Name<th>Price  [#list animals as animal]
  <tr>
    <td>      [#if animal.size == "large"]<b>[/#if]
      ${animal.name}      [#if animal.size == "large"]</b>[/#if]
    <td>${animal.price} Euros  [/#list]</table>

The alternative (square bracket) and the default (angle bracket) syntax are mutually exclusive within a template. That is, either the whole template uses alternative syntax, or the whole template uses the default syntax. If the template uses alternative syntax, things like <#if...> are count as static text, not as FTL tags. Similarly, if the template uses the default syntax, things like [#if ...] count as static text, not as FTL tags.

If you start the file with [#ftl ...] (where the ... stands for the optional parameters; of course [#ftl] works too) the file will surely use the alternative (square bracket) syntax. If you start the file with <#ftl ...> the file will surely use the normal (angle bracket) syntax. If there is no ftl directive in the file, then the programmer decides what the syntax will be by configuring FreeMarker (programmers seeConfiguration.setTagSyntax(int) in the API javadocs). Most probably the programmers use the factory default however. The factory default in 2.3.x is using the normal syntax. The factory default in 2.4.x will be auto-detection, which means that the first FreeMarker tag determines the syntax (it can be anything, not just ftl).

http://freemarker.incubator.apache.org/docs/dgui_misc_alternativesyntax.html

转载于:https://my.oschina.net/darrenshi/blog/632232