Jsoup: how to search for date text from a web page

Question

Just this is what I'm trying to do: (I want to use jsoup)

• • pass only one parsing URL
  • search by date (s) specified inside the content of the web page.
  • Retrieves at least one date from each page content.
  • convert this date to standard format

So, point number 1 What I have now:

String url = "http://stackoverflow.com/questions/28149254/using-a-regex-in-jsoup";
Document document = Jsoup.connect(url).get();

Now I want to understand what format the "Document" is, it already understands html or any type of web page type, or what?

Then Point # 2 Now I have:

Pattern p = Pattern.compile("\\d{4}-[01]\\d-[0-3]\\d", Pattern.CASE_INSENSITIVE | Pattern.DOTALL);
Elements elements = document.getElementsMatchingOwnText(p);

Here I try to match the date regex to search for dates on the page and store in a string for later use (point number 3), but I'm sure I'm not around, I need help here.

I made point number 4.

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, Advance!

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public static void main(String[] args){
    try {
        // using USER AGENT for giving information to the server that I am a browser not a bot
        final String USER_AGENT =
                "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.1 (KHTML, like Gecko) Chrome/13.0.782.112 Safari/535.1";

        // My only one url which I want to parse
        String url = "http://stackoverflow.com/questions/28149254/using-a-regex-in-jsoup";

        // Creating a jsoup.Connection to connect the url with USER AGENT
        Connection connection = Jsoup.connect(url).userAgent(USER_AGENT);

        // retrieving the parsed document
        Document htmlDocument = connection.get();

        /* Now till this part, I have A parsed document of the url page which is in plain-text format right?
         * If not, in which type or in which format it is stored in the variable 'htmlDocument'
         * */

        /* Now, If 'htmlDocument' holds the text format of the web page
         * Why do i need elements to find dates, because dates can be normal text in a web page,
         * So, how I am going to find an element tag for that?
         * As an example, If i wanted to collect text from <p> paragraph tag, 
         * I would use this : 
         */
        // I am not sure is it correct or not
        //***************************************************/
        Elements paragraph = htmlDocument.getElementsByTag("p");
        for(Element src: paragraph){
            System.out.println("text"+src.attr("abs:p"));
        }
       //***************************************************//

        /* But I do not want any elements to find to gather dates on the page
         * I just want to search the whole text document for date
         * So, I need a regex formatted date string which will be passed as a input for a search method
         * this search mechanism should be on text formatted page as we have parsed document in 'htmlDocument'
         */

        // At the end we will use only one date from our search result and format it in a standard form

        /*
         * That is it.
         */


        /*
         * I was trying something like this
         */
        //final Elements elements = document.getElementsMatchingOwnText("\\d{4}-\\d{2}-\\d{2}");
        Pattern p = Pattern.compile("\\d{4}-[01]\\d-[0-3]\\d", Pattern.CASE_INSENSITIVE | Pattern.DOTALL);
        Elements elements = htmlDocument.getElementsMatchingOwnText(p);

        for(Element e: elements){
            System.out.println("element = [" + e + "]");
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
}

Answer 1

, :

import org.jsoup.Connection;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

import java.util.List;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

/**
 * Created by ruben.alfarodiaz on 21/12/2016.
 */
@RunWith(JUnit4.class)
public class StackTest {

    @Test
    public void findDates() {
        final String USER_AGENT = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.1 (KHTML, like Gecko) Chrome/13.0.782.112 Safari/535.1";
        try {
            String url = "http://stackoverflow.com/questions/51224/regular-expression-to-match-valid-dates";
            Connection connection = Jsoup.connect(url).userAgent(USER_AGENT);
            Document htmlDocument = connection.get();
            //with this pattern we can find all dates with regex dd/mm/yyyy if we need cover extra formats we should create N more patterns
            Pattern pattern = Pattern.compile("(0?[1-9]|[12][0-9]|3[01])/(0?[1-9]|1[012])/((19|20)\\d\\d)");

            //Here we find all document elements which have some element with the searched pattern  
            Elements elements = htmlDocument.getElementsMatchingText(pattern);
            //in this loop we are going to filter from all original elements to find only the leaf elements
            List<Element> finalElements = elements.stream().filter(elem -> isLastElem(elem, pattern)).collect(Collectors.toList());
            finalElements.stream().forEach(elem ->
                System.out.println("Node: " + elem.html())
            );

        }catch(Exception ex){
            ex.printStackTrace();
        }
    }

    //Method to decide if the current element is a leaf or contains others dates inside  
    private boolean isLastElem(Element elem, Pattern pattern) {
        return elem.getElementsMatchingText(pattern).size() <= 1;
    }

}

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<html>
    <body>
        <div>
           20/11/2017    
        </div>
    </body>
</html>

dd/mm/yyyy, 3 html, body div, div