Java正则表达式 - 多行

Question

I have a large array with string. I need to use the string in the array to form patterns. However for the string in the text could be across several lines. the constructed patterns don't work with the multiline flag. Could anyone point out what is wrong? Thank you.

Here is my code:

String[] phrases = new String[2];
    phrases[0] = "student (male)";
    phrases[1] = "worker (female)";

    Pattern[] ptn = new Pattern[phrases.length];

    int i = 0;
    for (String p : phrases)
    {
        p = Pattern.quote(p);
        System.out.println(p);
        ptn[i] = Pattern.compile(p+"\\:\\s\\w+",Pattern.MULTILINE);
        i++;
    }

    String text = "student\n(male): John";
    System.out.println(text);

    for(Pattern p : ptn)
    {
        Matcher m = p.matcher(text);
        while(m.find())
        {
            System.out.println(m.group());
        }
    }

Answer 1

Here, you don't need that MULTILINE flag:

As @fge explained earlier, that flag only means that ^ (and $ ) will match the begin (and end ) of each line in the tested String.
Reminder: the default behavior (without that flag) would cause ^ and $ to match respectively the begin and the end of the whole String .

---

If you want to match, at some point, either a space or a new line , I would suggest you to try matching \\s .

However, if you replace the following lines:

phrases[0] = "student (male)";
phrases[1] = "worker (female)";

by:

phrases[0] = "student\\s(male)";
phrases[1] = "worker\\s(female)";

Then you won't be able to use Pattern#quote to escape the parenthesis. I believe that the simplest way is to directly escape them yourself as follow:

phrases[0] = "student\\s\\(male\\)";
phrases[1] = "worker\\s\\(female\\)";

---

If you actually can't modify these Strings, you may just change:

p = Pattern.quote(p);

for:

p = p.replaceAll("(\\(|\\))", "\\\\"+"$1").replaceAll(" ", "\\\\s");

This will:

• escape the ( and )
• replace the spaces ( ) by \\s to match either spaces or new lines.

Here is an Ideone link to some executable example of how your code could be :)

Hope it helps!