I am new to Jsoup I am suppose to do a screen scraping to obtain a hierarchy of links. I am able to get the links from the first page but I need to know how I can go deeper and get the link of each link. This is what i have so far. It prints out all the URLs but i want to go deeper and print the URL of each one too or if its too much at least i want to pick one URL example "* a: http://www.w3schools.com/html/default.asp (Learn HTML)" it is from the output and print all its child URL.
import org.jsoup.Jsoup;
import org.jsoup.helper.Validate;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import java.io.IOException;
/**
* Example program to list links from a URL.
*/
public class ListLinks {
public static void main(String[] args) throws IOException {
String url = "http://www.w3schools.com/";
print("Fetching %s...", url);
Document doc = Jsoup.connect(url).get();
Elements links = doc.getElementsByTag("a");
print("\nLinks: (%d)", links.size());
for (Element link : links) {
print(" * a: <%s> (%s)", link.absUrl("href") /*link.attr("href")*/, trim(link.text(), 35));
}
}
private static void print(String msg, Object... args) {
System.out.println(String.format(msg, args));
}
private static String trim(String s, int width) {
if (s.length() > width)
return s.substring(0, width-1) + ".";
else
return s;
}
}
Output:
Fetching http://www.w3schools.com/...
Links: (127)
* a: <> ()
* a: <http://www.w3schools.com/html/default.asp> (Learn HTML)
* a: <http://www.w3schools.com/html/html5_intro.asp> (Learn HTML5)
* a: <http://www.w3schools.com/css/default.asp> (Learn CSS)
* a: <http://www.w3schools.com/css3/default.asp> (Learn CSS3)
...
...
There's more URLs but i didn't want to display them all
You can iterate on each child URI and create a new JSOUP Document and then collect all the child links
example pseudocode:
download(String toplevelURI, int level) {
if (level > MAX_LEVEL) {
return; //termination condition
}
Document doc = Jsoup.connect(url).get();
Elements links = doc.getElementsByTag("a");
for (Element link : links) {
String url = link.absUrl("href");
link.add(url); //store the current level of link
download(url, level++); //get all children of current link
}
}
There are few things to take care of