Getting multiple matches via regex

问题

I want to retrieve a strings from a global string via Matcher & Pattern using REGEX.

String str = "<strong>ABC</strong>123<strong>DEF</strong>"
Pattern pattern = Pattern.compile("<strong>(.*)</strong>");
Matcher matcher = pattern.matcher(str);

My problem is that the matcher gives me just one match that is inside the global tag strong:

ABC</strong>123<strong>DEF

My objective is to get 2 matches:

ABC
DEF

Thank you very match for you help.

回答1:

You need a non greedy regex:

Pattern pattern = Pattern.compile("<strong>.*?</strong>");

Use ? to specify non greedy. This means it will match the first match it finds instead of the outer most match...

If you only want ABC and DEF then you can do something like this using lookaheads and lookbehinds:

String str = "<strong>ABC</strong>123<strong>DEF</strong>";
Pattern pattern = Pattern.compile("((?<=<strong>).*?(?=</strong>))");
Matcher matcher = pattern.matcher(str);
while(matcher.find())
{
    System.out.println(matcher.group());
}

If you do a google search you should be able to find information on lookaheads and lookbehinds...

回答2:

I recommend to use JSOUP to parse your HTML code instead of regex as

    Document doc = Jsoup.parse("<strong>ABC</strong>123<strong>DEF</strong>");

    // select your tag
    Elements elements = doc.select("strong");

    // get the iterator to traverse all elements
    Iterator<Element> it =  elements.iterator();

    // loop through all elements and fetch their text
    while (it.hasNext()) {
        System.out.println(it.next().text());
    }

Output :

ABC
DEF

or get Output as single string

    Document doc = Jsoup.parse("<strong>ABC</strong>123<strong>DEF</strong>");
    Elements elements = doc.select("strong");
    System.out.println(elements.text());

Output:

ABC DEF

Download Jsoup and add it as a dependency

来源：https://stackoverflow.com/questions/42120539/getting-multiple-matches-via-regex

标签

java

regex

pattern-matching