freemarker中的字符串比较不起作用

Question

<#if ${primaryName!}?has_content> && ${key?js_string!}=="Joe">
//do something

<#elseif ${primaryClass!}?has_content> && ${key?js_string!}=="Apple">
//do something

<#else>
//do something

</#if>

上面的内容给了我一个错误，即最后会发生一些事情。 { ] && .以上有什么问题？

Encountered "{" at line 26, column 39 in abc.ftl. Was expecting one of: ">" ... "." ... "[" ... "(" ... "?" ... "!" ... <TERMINATING_EXCLAM> ... "??" ... "+" ... "-" ... "*" ... "/" ... "%" ... "!=" ... "=" ... "==" ... ">=" ... <ESCAPED_GTE> ... ">" ... <ESCAPED_GT> ... <LESS_THAN_EQUALS> ... <LESS_THAN> ... ".." ... <AND> ... <OR> ...

Answer 1

是的，绝对会给你这样的东西

Encountered "{" ...
Was expecting one of:
    ">" ...
    "." ...
    "[" ...
    "(" ...
    "?" ...
    "!" ...

因为 if else 语法不正确，所以有几处是错误的。

下一行中突出显示的是错误的内容。

${primaryName!}?has_content> && ${key?js_string!}=="Joe">

您将数据放在数据模型中，但在 if/else foreach 的模板中，列出您可以直接访问它，而不是使用 ${}

这里是正确的，平等使用==，不平等使用!=

<#if primaryName?has_content && key?is_string && key=="Joe">
 // do somthing
<#elseif primaryClass?has_content && key?is_string && key=="Apple">
// elseif do something
<#else>
// else do something
</#if>

has_content 返回真。见doc

Note that when your data-model implements multiple template model interfaces you may get unexpected results. However, when in doubt you can use always use expr!?size > 0 or expr!?length > 0 instead of expr?has_content.

There is no js_string method , but its is is_string return true, if value is string 

查看is_string的文档

另见matchesBuilt-ins for strings