如何用正则表达式捕获代码中非注释区域的星号(*)？

Got it, let's work through how to correctly capture all asterisks (*) that aren't inside block comments in your code. First, let's break down why your original regex didn't work, then walk through reliable solutions.

问题分析：你的原正则的误区 #

The regex you tried [^\/\*[\S\s]*?\*\/\]\s*\*\s* uses a negated character set [^...], which only negates individual characters—not entire comment blocks. That means it's not actually excluding the full /* ... */ comment sections, so it won't give you the results you want.

方法1：使用(*SKIP)(*FAIL)语法（支持PCRE的引擎） #

If your regex engine supports PCRE syntax (like Python's re module, Java 9+, PHP, etc.), you can use this concise approach to skip comment blocks entirely and match only the asterisks outside them:

(/\*[\s\S]*?\*/)(*SKIP)(*FAIL)|\*

怎么理解这个正则？

• (/\*[\s\S]*?\*/): First, this matches any full block comment (including multi-line ones, since [\s\S] matches all characters, newlines included).
• (*SKIP)(*FAIL): This tells the regex engine to discard the matched comment block and not consider it as a valid match.
• |\*: Finally, this matches any remaining asterisk—these are the ones not inside comments.

When you run this against your test code:

/**
 * This function is useless
 *
 * @return sth
 */
public void testMe() {
 int x = 5*4;
 x*=7;
 x = x**2;
}

It will correctly match all 4 asterisks in 5*4, x*=7, and x**2, ignoring the ones in the comment block above.

方法2：先移除注释，再匹配星号（兼容所有引擎） #

If your regex engine doesn't support (*SKIP)(*FAIL) (like older Java versions), a more straightforward approach is to first strip all block comments from the code, then find all asterisks in the cleaned code.

For example, in Java:

// Your original code string
String code = "/**\n * This function is useless\n *\n * @return sth\n */\npublic void testMe() {\n int x = 5*4;\n x*=7;\n x = x**2;\n}";

// Remove all block comments
String codeWithoutComments = code.replaceAll("/\\*[\\s\\S]*?\\*/", "");

// Find all asterisks in the cleaned code
Pattern asteriskPattern = Pattern.compile("\\*");
Matcher matcher = asteriskPattern.matcher(codeWithoutComments);

// Iterate through matches
while (matcher.find()) {
    System.out.println("Found asterisk at index: " + matcher.start());
}

This will output the positions of the 4 asterisks in the testMe method, since all comment content has been removed first.

总结 #

• Use Method 1 if your engine supports PCRE syntax—it's clean and efficient.
• Use Method 2 for broader compatibility, especially with older regex engines.

Both approaches will reliably ignore asterisks inside /* ... */ comments and only target the ones in your actual code logic.

内容的提问来源于stack exchange，提问作者triandicAnt