使用正则表达式Java进行文本拆分

Question

I want to split the text with the help of regex, and then write each word in console from new line. But there is a problem, this email@mail.org is not considered as a word and I don't know what regular should be. I try to use look-ahead regex but it didn't help. Should I use the additional if statement to define words or just add something in my regex? Code:

Pattern p = Pattern.compile("\\s+[A-Za-z]++");
        Matcher m = p.matcher(text);
        while (m.find())
        {
                String s = m.group().replaceAll("\\s++", "");
                System.out.println(s);
        }

Answer 1

If all you want to do is to isolate each word from your text and print it out to the console, you can use String#split(String regex) and split on any amount of whitespace:

String[] words = text.split("\\s+");
for (String word : words) {
    System.out.println(word);
}

The logic here is focused on the whitespace which separates words, rather than worrying about how each actual word can be matched.

Answer 2

If you want to split on anything that isnt an upper or lowercase letter, for example split on numbers, spaces and symbols you could use:

String[] words = "some sentence".split("\\W+");

Essentially the reverse of what you were trying to do in your original question by providing a blacklist rather than a whitelist of allowed characters.

If you want to allow scenarios like email@mail.org and 12th and class those as words still, you could just split on a space or some sentence end character

String[] words = "some sentence".split("([\\W\\s]*\\s+)");

This will split the following:

email@mail.org x becomes email@mail.org and x

hello world becomes hello and world

hello, world becomes hello and world

hello; world hello; world becomes hello and world

hello (world) becomes hello and world and (make sure you filter out empty components)

hello. World hello. World becomes hello and world