Create a Web Scraper in Java

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Web Scraping is also called data scraping, web harvesting, or web crawling which is used to extract data from the web pages. A web scraper can use different approaches to extract information. For instance, XPath, CSS selectors, custom filters, HTML navigation, etc. In accordance with such scenarios, this article covers how to create a web scraper programmatically in Java.

• Java Web Scraping Library Configuration
• Web Scraping with HTML Navigation in Java
  • Inspection of HTML Documents and Their Elements in Java
  • Custom Filter Usage for Web Scraper in Java
• Web Scraping using XPath Query in Java
• Web Scraping with CSS Selector in Java

Java Web Scraping Library Configuration

Aspose.HTML for Java API supports offers web scraping features using different techniques. You can simply access the API by downloading the JAR files from the Downloads page or use the following Maven configurations in the pom.xml file of your project:

Repository

 <repositories>
     <repository>
         <id>snapshots</id>
         <name>repo</name>
         <url>http://repository.aspose.com/repo/</url>
     </repository>
</repositories>

Dependency

 <dependencies>
    <dependency>
        <groupId>com.aspose</groupId>
        <artifactId>aspose-html</artifactId>
        <version>21.12</version>
        <classifier>jdk16</classifier>
    </dependency>
</dependencies>

Web Scraping with HTML Navigation in Java

You can work with the Node class in order to navigate HTML pages. The code snippet below demonstrates how to navigate an HTML document in Java:

Inspection of the HTML Document and its Elements in Java

You can work with the element traversal method to navigate the HTML pages. The code sample below elaborates on how to inspect HTML documents in Java.

Custom Filter Usage for Web Scraper in Java

You can set a custom filter to skip or accept specific filters to work with the web scraper in Java. The code sample below elaborates on how to work with the custom or user-defined filters in a web scraper using Java:

Subsequently, after setting up a custom filter, you can easily navigate an HTML page using the code snippet below:

Web Scraping using XPath Query in Java

You can select different nodes of an HTML document by different criteria using XPath. The code below demonstrates how to perform web scraping using XPath Query in Java:

Web Scraping with CSS Selector in Java

You can search the needed items in a web scraper using the CSS selector. You can specify a parameter as a query selector and then a list of matching the selector is returned to the web scraper. The following code sample exhibits how to use CSS selector in a web scraper using Java:

Conclusion

In this article, you have explored different methods which can be used to create a web scraper in Java. You only need to make a few API calls using Aspose.HTML for Java library to create a web scraper in Java. You can explore the HTML Navigation, CSS Selector, Custom filter, and XPath Query techniques in this article. Furthermore, please feel free to get in touch with us via the forum if you need any further information or any assistance.

See Also

Convert EPUB to XPS in Java