Using Proxies with Java Web Scraping

While the 20th century was all about time being money, the current digital era is more inclined to data being money. Besides, do you know what’s common between a CEO of a multinational company, an entrepreneur, and a marketer? Well, they all gain valuable insights using data collected from different sources and strategize their action plans.

Data is now a pivotal differentiator that is the core of business strategies and market research for every industry.

No doubt we are accelerating our transformation to a data-driven world. Data collection using web scraping has increasingly become an integral part of several organizations as it provides a fast, flexible, and inexpensive way to gather data over the internet.

But what is web scraping? Why should you use Java web scraping code for an application? Most importantly, when we can collect data through web scraping, what do we need proxies for?

To help you out, here is the breakdown of everything you will need to know about scraping and proxies.

Understanding Web Scraping

Web scraping refers to the process of collecting data and other content information from a website over the internet. Simply put, web scraping is the technique of extracting data from the internet. All the collected data is then exported in the API, CSV, or spreadsheet format whichever is more convenient for the user to understand.

Previously, individuals used to copy and paste the required information manually, but it is not an effective way, especially if they want data from a large and complex website.

With web scraping, the data extraction process gets automated, making it easier to extract data from any web page regardless of the size and type of data. Some of the Web Scraping applications include competitive analysis, fetching images and product descriptions, aggregating new articles, extracting financial statements, predictive analysis, real-time analytics, machine learning training models, data-driven marketing, lead generation, content marketing, SEO monitoring, and monitoring sentiments of customers.

But web scraping also has some limitations. For instance, you may not face any problems if you are scraping a small website, but trying to fetch data from a large-scale website or search engine like Google your requests can be blocked either due to IP rate limitations or IP Geolocation.

And that’s where proxies come to your rescue.

Understanding Proxies

Proxies are like middlemen residing between the client and the website server. They are used for disguising the client-side IP address and optimizing connection routes. To avoid IP blocking while web scraping, proxies are used to cloak or change their IPs and create anonymity. Some of the proxies that can be used are transparent proxy, high anonymity proxy, distorting proxy, data center proxy, residential proxy, public proxy, private proxy, shared proxy, dedicated proxy, mobile proxy, SSL proxy, rotating proxy, and reverse proxy.

But, it still doesn’t answer where Java fits in all this, right?

Don’t fret! We will help you understand in the next section.

Using jsoup for Web Scraping

Being the oldest yet most popular language, Java allows the creation of highly reliable and scalable services as well as data extraction solutions (multi-threaded) using its libraries like HTMLUnit, Jaunt, or jsoup.

In this blog, we will cover how jsoup can help you with web scraping, but first, let’s take a brief look at what it is.

jsoup, an open-source Java library, is used to parse, manipulate, and extract data from JSON data payloads or HTML pages through a headless browser. Some capabilities of jsoup include

• Searching and extracting data through CSS selectors or DOM traversal.

• Immaculate user content to avoid Cross-Site Scripting (XSS) attacks.

• HTML is scraped and parsed from files, URLs, and strings.

• Manipulating attributes, elements, and texts in HTML.

• HTML tidy output.

To use jsoup for web scraping, download the jsoup jar file and add the jsoup library to the project.

If you use Gradle to manage Java project dependencies, you can implement jsoup as follows:

// jsoup HTML parser library @ https://jsoup.org/
implementation 'org.jsoup:jsoup:1.15.3'

While using Maven, you won’t have to download the jar file rather you can add it in the dependencies of project object model section as follows:

<dependency>
  <!-- jsoup HTML parser library @ https://jsoup.org/ -->
  <groupId>org.jsoup</groupId>
  <artifactId>jsoup</artifactId>
  <version>1.15.3</version>
</dependency>

What makes jsoup a great choice is it is self-contained hence there are no dependencies for runtime. It not only runs on Java 8 and up but also on Kotlin, Scala, Google App Engine, Lambda, and OSGi.

Moreover, if you want to create some changes, you will need to build a jar from the source in GIT to stay updated or reverse your changes. To do that, run the integration and unit test and install a snapshot jar into the Maven repository as follows:

git clone https://github.com/jhy/jsoup.git
cd jsoup
mvn install

Then parse the HTML page to extract in your Java code as:

//Pass Input Argument (URL)
try {
  Document page= Jsoup.connect("https://www.decipherzone.com/").get();
 } catch (IOException e){
  logger.error(e.getMessage());
}

To extract data with jsoup, you can either use DOM methods like getElementsByAttribute(String key),getElementsByClass(String className), or Sibling Elements: siblingElements(), firstElementSibling(), lastElementSibling(); nextElementSibling(), previousElementSibling() or selector-syntax.

You can extract data from different sites for eCommerce price comparison and monitoring, data mining, web indexing, market research, social listening, collecting sales leads, market research, and more.

In the above-mentioned code, jsoup loads and parses HTML content into an object, Jsoup class connects the method to the URL of the page, and the get method retrieves the web page data.

How to Use Proxies in your Java Web Scraping Software?

If you want to add a proxy to jsoup web scraping and avoid getting your IP address blocked, then you will have to add the proxy server details prior to connecting to the URL. For that, you need to use the System class’ setProperty method and define the property of the proxy.

For example, you can set the proxy as follows:

//set HTTP proxy host to 123.21.4.23
System.setProperty("http.proxyHost", "123.21.4.23");

//set HTTP proxy port to 2000
System.setProperty("http.proxyPort", "2000");

And in case, you need to authenticate the proxy server requires then define it this way:

System.setProperty("http.proxyUser", "<insert_username>");
System.setProperty("http.proxyPassword", "<insert_password>");

Conclusion

So that was it for using proxies with Java Web Scraping applications. We hope it helped you understand everything you need to know about web scraping, jsoup, and adding proxies to extract data from web pages.

However, we have just scratched the surface here and there are a lot of ways to do so as Java includes many other libraries that you can use to create web scraping solutions while adding proxies to them.

Summing it up, Java is a powerful language for developing web apps for almost every use case and data extraction for analysis is no exception. Moreover, the tools and libraries that have been created to perform different tasks by its community are exceptionally good, making it one of the best options to develop web scraping solutions.

With a good knowledge of web scraping and proxies, it will become easier for you to gather data, analyze it, and create strategies and content that users want for your website and lure them into buying your products and services.