使用否定的超前断言，(?! pattern).

Use negative lookahead assertion, (?!pattern).

    String[] tests = {
        "A wild adventure",      // true
        "A wild wild adventure"  // false
    };
    for (String test : tests) {
        System.out.println(test.matches("(?!.*\\b(\\w+)\\s\\1\\b).*"));
    }

由里克·梅瑟姆(Rick Measham)的 explain.pl :

REGEX: (?!.*\b(\w+)\s\1\b).*
NODE                     EXPLANATION
--------------------------------------------------------------------------------
  (?!                      look ahead to see if there is not:
--------------------------------------------------------------------------------
    .*                       any character except \n (0 or more times
                             (matching the most amount possible))
--------------------------------------------------------------------------------
    \b                       the boundary between a word char (\w)
                             and something that is not a word char
--------------------------------------------------------------------------------
    (                        group and capture to \1:
--------------------------------------------------------------------------------
      \w+                      word characters (a-z, A-Z, 0-9, _) (1
                               or more times (matching the most
                               amount possible))
--------------------------------------------------------------------------------
    )                        end of \1
--------------------------------------------------------------------------------
    \s                       whitespace (\n, \r, \t, \f, and " ")
--------------------------------------------------------------------------------
    \1                       what was matched by capture \1
--------------------------------------------------------------------------------
    \b                       the boundary between a word char (\w)
                             and something that is not a word char
--------------------------------------------------------------------------------
  )                        end of look-ahead
--------------------------------------------------------------------------------
  .*                       any character except \n (0 or more times
                           (matching the most amount possible))

另请参见

• regular-expressions.info/环顾
• 在Java中使用正则表达式
  • 使用前瞻性否定符号来确保字符串中没有出现多次的字符
  • 使用断言的许多示例
  • 使用环顾四周的非常有启发性的示例

  否定断言仅在您还想肯定匹配其他模式时才有意义(请参见上面的示例).否则，您可以使用布尔补码运算符！来以您之前使用的任何模式对 matches 求反.

  Negative assertions only make sense when there are also other patterns that you want to positively match (see examples above). Otherwise, you can just use boolean complement operator ! to negate matches with whatever pattern you were using before.

  String[] tests = {
      "A wild adventure",      // true
      "A wild wild adventure"  // false
  };
  for (String test : tests) {
      System.out.println(!test.matches(".*\\b(\\w+)\\s\\1\\b.*"));
  }