正则表达式与单词模式不匹配

Question

I have written code in Java which will return true if the matching string contains word or words. But it is returning false .

public class RegexTestStrings {
  public static final String EXAMPLE_TEST = "This is my small example "
      + "string which I'm going to " + "use for pattern matching.";

  public static void main(String[] args) {
    System.out.println(EXAMPLE_TEST.matches("(\\w)*"));
  }
}

Can anyone spot my mistake?

Answer 1

matches() tests the entire string. You need to use find() or extend your regex with .* :

.*(\\w)+.*

Please note, that I changed * to + .

I would prefer find() for performance reasons.

Answer 2

如果您只需要测试字符串是否匹配并且不需要获取组，就足够了

".*\\w+.*"

Answer 3

正如您在文档中看到的，\\ w匹配字母和数字，而不是空格或符号。

Answer 4

From the javadoc

\\w A word character: [a-zA-Z_0-9]

As you see there is no space, no single quote and no dot. So your regexp cannot match the test string since it contains those charachtes.

The following prints true for your test string

System.out.println(EXAMPLE_TEST.matches("(\\w|\\s|\\p{Punct})*"));