用于检查Java中以字符'@'开头的单词的出现的正则表达式

Question

I am trying to search for occurrence of a word starts with '@', Say @steve . But I have no success.

What I have tried so far is this ". \\b@steve\\b. " but \\b matches only words which starts with [a-zA-Z0-9_].

If the question is too broad or anybody needs a code sample please let me know I'll post

Any help is appreciated.

Thanks

Answer 1

You're correct, a \\b can't find a word-boundary there because @ isn't a word character. You could use a look-behind:

(?<!\\w)@steve\\b

Regex101 Example

A general case regex would simply be:

(?<!\\w)@\\w+

Note that in the above regex, the ending \\b is unnecessary because the quantifier will go to the end of the word anyway.

Answer 2

I think this is what you are looking for.

(?<!\w)@\w+

This matches @Steve but doesn't match Hello@Steve. 

Answer 3

Try this regex:

@\\b\\w+\\b

You can test regexes here

Answer 4

public static void main(String[] args)
{
    char[] word = "@SomeWord".toCharArray();
    if (word[0] == '@')
    {
        System.out.println("Starts with @");
    }
    else
    {
        System.out.println("Not Starts with @");
    }

}