A web crawler is essentially an internet bot that is used to scan the internet, going through individual websites, to analyze the data, and generate reports. Most internet giants use prebuilt web crawlers all the time to study their competitor sites.
GoogleBot is Google’s popular web crawler, crawling 28.5% of the internet. It includes advertising bots, image bots, search engine bots, and the likes. This is followed by Bing with 22%.
Why Are Web Crawlers Useful?
For every website that hopes to have a strong online presence, it becomes imperative to use a web crawler. The whole idea is to be able to visit competitor sites and extract information like product details, pricing, and images. In effect, each of these companies should aim to do better than their competitor websites. While web crawling exists in every online industry, here are some of the important use cases.
- A popular fashion eCommerce store based in the United States, uses web crawling to access information and data from a hundred other fashion sites. This helps them stay updated about their competitors.
- A US eCommerce platform uses web crawling to determine and ascertain a pricing strategy based on zip codes or locations of the consumers.
- A furniture company based out of Europe accesses data from 20 of its competitor sites to gather insights.
- Also, by using product information crawled from Amazon, an Indian retailer website identifies and determines its best seller products.
How To Create A Web Crawler In Java?
Creating a web crawler in Java will require some patience. This needs to be accurate and efficient. Here are some steps to follow to make a simple web crawler prototype using Java.
- Set up a MySQL database
The first step requires setting up a MySQL database to start work. If you are working on a Windows system, you can simply download it and get it installed within a few minutes. Thereafter, you could use any GUI interface to operate on MySQL.
- Database and table setup
Next, you could create a new database called Crawler in MySQL and a new table called Record.
- Web crawling using Java
Finally, download the JSoup core library and get started with web crawling. You could then create a new project called ‘Crawler’ in Eclipse and add JSoup and MySQL-connector jar paths to the Java Build Path. Thereafter, you can create two classes. One would be called DB, used for handling the database, and the other would be the Main crawler. At this point, you can put in the links you are looking to crawl and get going!
Remember, you’ll also need to set up a connection with a residential proxy to get data from websites in a location different from your own physical location. Without a residential proxy, you might be automatically blocked from scraping a website or scrape data from the wrong country.
How To Save Time Instead With A Prebuilt Scraper
While creating a new web crawler with Java is an interesting task, it requires a lot of time, coding, and effort. And you would have to maintain the code accurately for bringing out efficient results.
But, how useful would it be if you could use some scraping tools to get your job done quicker? Well, with prebuilt scrapers, all you have to do is insert the links you are looking to scrape, set the crawl limit, and you are good to go!
The best part about these tools is that they do not require a lot of programming skills. These are coded in the backend and are ready for use. Zenscrape provides ready-made scraping services based on your requirements. There are free and paid scraping plans based on Javascript rendering. With easy to use APIs, this web scraping tool can provide you results quickly.
Data Crawling Vs Data Scraping
Data crawling and data scraping are two very similar concepts. While fundamentally, they act in the same way, there are certain differences between the two.
First and foremost, data crawling refers to crawling web pages and downloading them. On the other hand, data scraping is a broader term that caters to scraping information from various sources. The internet is one of the many sources for scraping.
Secondly, handling duplicate data is an important feature for data crawling. The internet is a broad and open-ended platform. Very often, content is duplicated across multiple websites. If normal scraping methods are used, duplicate content will not be factored in. On the other hand, advanced web crawling mechanisms can take care of that so that the end-users do not get unnecessary data.
As compared to data scraping methods, data crawling is intelligent and uses advanced methods. For instance, crawling a website multiple times can call for some friction. Thus, web crawlers also need to know how much to dig into each site.
Finally, different web crawlers survey the same website at the same time. Or this, it is imperative to avoid collisions and conflicts for efficient results. The story is very different for data scraping. They can move around with a lot more freedom and work independently.
Is coding your own crawler the better option?
Creating web crawlers using Java is the traditional method. It requires a high level of programming to develop and maintain the code. However, in today’s world of convenience, it seems silly not to opt for prebuilt, faster crawling and scraping tools like Zenscrape. The only benefit to going the DIY approach is being able to build the exact inner workings yourself.
If you want to get started using a web scraper, click here to watch some useful free tutorials.
