#Dynamic website examples how to#
#Dynamic website examples code#

The described knowledge is a bare minimum for creating a fully featured web scraper.ДЄlso, I've intentionally skipped Selenium from the article, as it is not the most straightforward library from my sight. Still, I hope that this reading helps get the first steps in web scraping and structuring data extraction information. The Java Web Scraping topic is enormous, so it's hard to cover all the extensive parts like the proxies, multithreading, deployment, etc., in one article. Thread-safe, as it only requires dealing with HTTP calls.What are the benefits of using a web scraping API? The result will contain already rendered HTML, which is ready for the less CPU-consuming operation - parsing. The idea behind it is to specify the API token while making a call with OkHttpClient and parse JSON response using Gson.

#Dynamic website examples code#

What is the most straightforward way of overcoming it? Sure, let's use a browser (and pretend to be a real user)! Simple dynamic website #ДЇor demonstration purposes, I've created a simple dynamic website with the following content (source code can be found here: ):ДЇor obtaining your API token, please, log in to the ScrapingAnt dashboard. It provides a better user experience for end-users but makes it harder to extract data from such web pages. Actually, it happens and supports by all modern browsers, so you even may not notice such behavior during web surfing.ДЄlso, the website can use the simpler technology of dynamic content load - XHR. It also requires executing the web page's Javascript code which dynamically loads data. Modern websites tend to use SPA (Single Page Application) technology to serve content, which means that it's not enough to just make an HTTP request to a server for receiving content in your web scraper. Well, we've reached the most exciting part of this article: headless browsers.

#Dynamic website examples how to#

HTMLCleaner documentation Headless browsers: how to scrape a dynamic website with Java # Also, the lack of documentation makes it hard to find out relevant information. My impression about HTMLCleaner is that this library has the HTML parsing approach, which is not widely used across the web scraping community, and it might be confusing. The following code snippet shows how to get the HTML content: The main advantage of using those classes is that they will be available in any version of Java you're using. It's also HTTPS supporting counterpart HttpsURLConnection was introduced in Java 1.4. HttpURLConnection is the maturest of the clients we're comparing, and probably the most used in the Java ecosystem launched way back in version 1.1 of the JDK. We will check out several most common libraries with examples of making requests using them. Sometimes HTTP client may be the only library needed for the web scraper, as it can cover requesting and receiving HTML content from the server. Making an HTTP request is a basis for most web scrapers, as the website's data is served using this commonly spread protocol. How to make a request: HTTP client libraries #

Let's move forward and check out valuable tools that cover data extraction needs. You can replace this part with an API call response, DB storing function, or displaying the data in UI. Not the most impressive part of the program, but this abstraction is required to use web scraping results.

Let's create a simple Java web scraper, which will get the title text from the site to observe how to cover each aspect on practice:

data parsing (pick only the required information).

data extraction (retrieve required data from the website).

To create a complete web scraper, you should consider covering a group of the following features:

All those parts are essential, as not every website provides an API to access their data. In this article, we're going to explore different aspects of Java web scraping: retrieving data using HTTP/HTTPS call, parsing HTML data, and running a headless browser to render Javascript and avoid getting blocked. Let's check out the main concepts of web scraping with Java and review the most popular libraries to setup your data extraction flow.

It allows creating highly-scalable and reliable services as well as multi-threaded data extraction solutions. Java is one of the most popular and high demanded programming languages nowadays.