How can I find whitespace in a String?

Question

How can I check to see if a String contains a whitespace character, an empty space or " ". If possible, please provide a Java example.

For example: String = "test word";

Answer 1

Check whether a String contains at least one white space character:

public static boolean containsWhiteSpace(final String testCode){     if(testCode != null){         for(int i = 0; i < testCode.length(); i++){             if(Character.isWhitespace(testCode.charAt(i))){                 return true;             }         }     }     return false; } 

Reference:

• Character.isWhitespace(char)

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Using the Guava library, it's much simpler:

return CharMatcher.WHITESPACE.matchesAnyOf(testCode); 

CharMatcher.WHITESPACE is also a lot more thorough when it comes to Unicode support.

Answer 2

For checking if a string contains whitespace use a Matcher and call its find method.

Pattern pattern = Pattern.compile("\\s"); Matcher matcher = pattern.matcher(s); boolean found = matcher.find(); 

If you want to check if it only consists of whitespace then you can use String.matches:

boolean isWhitespace = s.matches("^\\s*$");