How can I get a part of a String in Java?

Question

I have Strings like this:

fields {
  key: "ristorante"
  value {
    string_value: ""
  }
}
fields {
  key: "type"
  value {
    list_value {
      values {
        string_value: "pizza"
      }
    }
  }
}

And I need to extract just the string_value of type, in this case the word pizza .

How can I do it in Java?

I don't want the answer for this specific case, I just want to know how to extract some text from a String or if is better to parse it to a JSON, and how to do it.

Answer 1

Pattern pattern = Pattern.compile("values[^s]+?string_value\\s?:\\s?\"(.*?)(?<!\\\\)\"");
Matcher matcher = pattern.matcher(text);
if (matcher.find()) {
    String value = matcher.group(1);
    System.out.println(value);
}

Use this regex if you really only want to get the 'pizza' value

If you want to get all 'string_value' entries use

"string_value\\s?:\\s?\"(.*?)(?<!\\\\)\""

as the regex pattern. You will then find multiple occurrences, so use a while loop instead of if (matcher.find)

(Regex will probably be a little bit faster than parsing it with JsonParser)