正则表达式匹配可能包含嵌入式JSTL的空白HTML标记？ [英] Regular expression to match empty HTML tags that may contain embedded JSTL?

问题描述

我试图构造一个正则表达式来查找可能嵌入JSTL的空html标签。我使用Perl进行匹配。

到目前为止，我可以将任何不包含JSTL的空html标签与以下内容匹配？

  / <\ w + \ b（？！：）[^ <* *>> \ s *< \ / \ w + / si 
  

\b（？！：）会避免匹配开头JTSL标签，但是没有说明JSTL是否可以在HTML标签内（这是允许的）。我只想知道这个HTML标签是否没有孩子（只有空白或空白）。所以我正在寻找一种可以匹配以下两种模式：

 < div id =my-id> ; 
< / div> 
< div class =< c：out var =$ {my.property}/>>< / div> 
  

目前第一个div匹配。第二个不是。它可行吗？我用前瞻断言尝试了几个变体，我开始认为它不是。 然而，我不能肯定地说，或者说清楚为什么它不是。

编辑：我不是写一些东西来解释代码，我对使用解析器不感兴趣。我正在写一个脚本来指出潜在的问题/疏忽。此时，我也很好奇，以查看是否有可能缺少的lookahead或lookbehinds的内容。如果它困扰你，我试图用这种方式解决一个问题，不要把它看作是寻求解决方案。对我来说，现在这是一个更大的挑战，也是一个了解更多正则表达式的机会。

解决方案

试试

  ≤（\w +）（?: \s + \w + = [^] +（?: \ $ [^] + [^] +）？）* GT; \ s *< / \ 1> 
  

一个简短的解释：

 <＃match a'<'
（\ w +）＃匹配一个或多个az，AZ，0-9或'_'并将其存储在组1中
（？：＃打开不匹配组1 
 \ s +＃匹配一个或多个空格字符
 \ w +＃匹配一个或多个az， AZ，0-9或'_'
 =＃match'='
 [^] +＃匹配除'''之外的一个或多个字符
（？：＃open不匹配组2 
\ $＃match'$'
 [^] +＃匹配除'''之外的一个或多个字符
＃match'' 
 [^] +＃匹配除'''之外的一个或多个字符
）＃＃关闭不匹配-g roup 2，并使其成为可选
＃match''
）*＃关闭非匹配组1，并重复其自身零次或多次
> ＃match'>'
 \s *＃匹配零个或多个空格字符
< / \ 1> ＃match'< / X>'其中`X`是组1中捕获的内容
  

适用于你的两个例子，但我相信有人可以构造你想匹配的html，但不会被正则表达式匹配。但在阅读完编辑之后，似乎你已经意识到了这一点。

I'm trying to construct a regular expression to look for empty html tags that may have embedded JSTL. I'm using Perl for my matching.

So far I can match any empty html tag that does not contain JSTL with the following?

/<\w+\b(?!:)[^<]*?>\s*<\/\w+/si

The \b(?!:) will avoid matching an opening JTSL tag but that doesn't address the whether JSTL may be within the HTML tag itself (which is allowable). I only want to know if this HTML tag has no children (only whitespace or empty). So I'm looking for a pattern that would match both the following:

<div id="my-id"> 
</div>
<div class="<c:out var="${my.property}" />"></div>

Currently the first div matches. The second does not. Is it doable? I tried several variations using lookahead assertions, and I'm starting to think it's not. However, I can't say for certain or articulate why it's not.

Edit: I'm not writing something to interpret the code, and I'm not interested in using a parser. I'm writing a script to point out potential issues/oversights. And at this point, I'm curious, too, to see if there is something clever with lookaheads or lookbehinds that I may be missing. If it bothers you that I'm trying to "solve" a problem this way, don't think of it as looking for a solution. To me it's more of a challenge now, and an opportunity to learn more about regular expressions.

Also, if it helps, you can assume that the html is xhtml strict.

解决方案

Try

<(\w+)(?:\s+\w+="[^"]+(?:"\$[^"]+"[^"]+)?")*>\s*</\1>

A short explanation:

<            # match a '<'
(\w+)        # match one or more a-z, A-Z, 0-9 or '_' and store it in group 1 
(?:          # open non-matching-group 1
  \s+        #   match one or more white space characters 
  \w+        #   match one or more a-z, A-Z, 0-9 or '_'
  ="         #   match '="'
  [^"]+      #   match one or more characters other than '"'
  (?:        #   open non-matching-group 2
    "\$      #     match '"$'
    [^"]+    #     match one or more characters other than '"'
    "        #     match '"'
    [^"]+    #     match one or more characters other than '"'
  )?         #   close non-matching-group 2, and make it optional
  "          #   match '"'
)*           # close non-matching-group 1, and make repeat itself zero or more times
>            # match '>'
\s*          # match zero or more white space characters
</\1>        # match '</X>' where `X` is what is captured in group 1

This works for both you examples but I am sure someone can construct html that you want to match but will not be matched by the regex. But after reading your 'edit', it seems you are aware of that.

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