Java正则表达式校验需求：匹配数字、括号、AND/OR及空格

Got it, let's sort out that regex you're working on. The key issue with your previous attempts is that you were trying to fit AND/OR into a character class (which only handles single characters), but those are multi-word keywords that need to be matched as whole units.

The Correct Regex #

Here's a regex that meets all your requirements:

^((AND|OR)|\d|\s|\(|\))+$

Breakdown of the Pattern #

Let's break down each part so you understand how it works:

• ^ and $: Anchors to ensure the entire string is validated (no extra characters before or after allowed content)
• (AND|OR): Matches the complete keywords AND or OR as whole units (prevents partial matches like AN or O from being allowed)
• \d: Matches any digit (0-9, equivalent to [0-9])
• \s: Matches any whitespace character (spaces, tabs, etc. – adjust to if you only want literal spaces)
• \( and \): Matches opening and closing parentheses (we don't enforce proper nesting here since your stack-based code handles that)
• +: Ensures there's at least one valid character in the string (blocks empty inputs)

Testing Against Your Examples #

This regex will correctly validate all your sample inputs:

• Valid: 1OR2, 2, 1 OR 2 OR 15, ( 2OR3) AND 1, (12AND13 AND1)OR(4 AND5), ((2AND3 AND 1)OR(4AND5))AND6
• Also valid (as requested): ())34AND(4 (even with mismatched parentheses, since your stack code handles that check separately)

Java Implementation Example #

Here's how you'd use this in your Java code:

import java.util.regex.Pattern;

public class ValidationExample {
    public static void main(String[] args) {
        String validationRegex = "^((AND|OR)|\\d|\\s|\\(|\\))+$";
        Pattern pattern = Pattern.compile(validationRegex);
        
        // Test a valid input
        String validInput = "(12AND13 AND1)OR(4 AND5)";
        System.out.println(pattern.matcher(validInput).matches()); // Outputs true
        
        // Test an invalid input (contains 'X')
        String invalidInput = "1ORX2";
        System.out.println(pattern.matcher(invalidInput).matches()); // Outputs false
    }
}

Optional: Case Insensitivity #

If you need to allow lowercase or mixed-case versions like and or Or, add the case-insensitive flag ((?i)) to the regex:

^((?i)AND|OR|\d|\s|\(|\))+$

内容的提问来源于stack exchange，提问作者Mikke