f:validateRegex输入无效字符后不显示任何消息 [英] f:validateRegex doesn't show any message after typing invalid character

问题描述

我正在使用JSF.带有用于验证的代码:

I'm using JSF. With code for validating:

<h:inputText id="sender" value="#{contactForm.sender}">
      <f:validateRegex pattern="([a-zA-Z_0-9]).{4,32}" />
</h:inputText>

当我输入字符串时:abc.结果无效.好的. 然后我输入:abcd @.我以为该字符串无效，因为该字符串包含@ letter.但是我没有收到任何消息.这意味着该字符串是有效的.我对正则表达式不太清楚.你能帮忙吗?

When i type a string: abc. The result is invalid. Good. Then i type: abcd@ . I thought, that string is invalid because that string contains @ letter. But i don't recieve any messages. That means that string is valid. I don't understand about regex clearly. Can you help?

推荐答案

您忘记了转义与输入字符串中任何字符匹配的.元字符

You forgot to escape the . meta-character which matches any character in the input string

([a-zA-Z_0-9]).{4,32}
//            ^
//            |
//            |
//        Notice the dot . this matches any character

因此，您的正则表达式将匹配任何以小写，大写字符或下划线_或0和9之间的数字开头的字符串，然后是重复4至32次的任何字符，因此这几乎匹配任何内容

So you regular expression will match any string starting with lowercase, uppercase character or an underscore _ or a number between 0 and 9 followed by any character repeated between 4 and 32 times, so this almost matches anything.

要解决此问题，您必须转义点.并将其包含在第一组中，如下所示，-当然可以使用\w代替[a-zA-Z_0-9]，因为它们相同也是-:

To fix this you have to escape the the dot . and include in the first group, something like the following, - of course you can use \w instead of [a-zA-Z_0-9] as they are the same thing too -:

([\w\.]){4,32}

.点必须进入组内，否则表达式将匹配与以前相同的任何字符串，但随后包含4到32个点，而现在它将匹配包含字母字符或数字或点或下划线，长度在4到32个字符之间.

The . dot has to go inside the group or the expression will match any string starting with the same as before but then contains between 4 and 32 dots, whereas now it will match any string that contains alphabetical characters or numbers or dots or underscores with a length between 4 and 32 characters.

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