Web scraping is useful to programmatically extract data from websites. Often you need to scrape multiple pages from a site to gather complete information. In this article, we'll see how to scrape multiple pages in Java using the JSoup library.
Prerequisites
To follow along, you'll need:
<dependency>
<groupId>org.jsoup</groupId>
<artifactId>jsoup</artifactId>
<version>1.13.1</version>
</dependency>
Import JSoup
We'll need the following import:
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
Define Base URL
—
We'll scrape a blog -
<https://copyblogger.com/blog/>
<https://copyblogger.com/blog/page/2/>
<https://copyblogger.com/blog/page/3/>
Let's define the base URL pattern:
String baseUrl = "<https://copyblogger.com/blog/page/%d/>";
The
Specify Number of Pages
Next, we'll specify how many pages to scrape. Let's scrape the first 5 pages:
int numPages = 5;
Loop Through Pages
We can now loop from 1 to
for (int page = 1; page <= numPages; page++) {
// Construct page URL
String url = String.format(baseUrl, page);
// Code to scrape each page
}
Send Request and Parse HTML
Inside the loop, we'll send a GET request and parse the HTML using JSoup:
Document doc = Jsoup.connect(url).get();
Elements articles = doc.select("article");
This gives us Elements containing the article nodes to extract data from.
Extract Data
Now within the loop we can extract information like title, URL, author etc from each article:
String title = article.select("h2.entry-title").text();
String url = article.select("a.entry-title-link").attr("href");
String author = article.select("div.post-author a").text();
Full Code
Our full code to scrape 5 pages is:
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import java.io.IOException;
import java.util.ArrayList;
public class WebScraper {
public static void main(String[] args) throws IOException {
String baseUrl = "https://copyblogger.com/blog/page/%d/";
int numPages = 5;
for (int page = 1; page <= numPages; page++) {
String url = String.format(baseUrl, page);
Document doc = Jsoup.connect(url).get();
Elements articles = doc.select("article");
for (Element article : articles) {
String title = article.select("h2.entry-title").text();
String url = article.select("a.entry-title-link").attr("href");
String author = article.select("div.post-author a").text();
Elements categories = article.select("div.entry-categories a");
ArrayList<String> catTexts = new ArrayList<>();
for (Element cat : categories) {
catTexts.add(cat.text());
}
System.out.println("Title: " + title);
System.out.println("URL: " + url);
System.out.println("Author: " + author);
System.out.println("Categories: " + catTexts);
}
}
}
}This allows us to scrape and extract data from multiple pages sequentially in Java using JSoup. The code can be extended to scrape any number of pages.
Summary
Web scraping enables collecting large datasets programmatically. With the techniques here, you can scrape and extract information from multiple pages of a website in Java.
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With the power of Proxies API combined with Python libraries like Beautiful Soup, you can scrape data at scale without getting blocked.