Book Image

Instant jsoup How-to

By : Pete Houston
Book Image

Instant jsoup How-to

By: Pete Houston

Overview of this book

As you might know, there are a lot of Java libraries that support parsing HTML content out there. Jsoup is yet another HTML parsing library, but it provides a lot of functionalities and boasts much more interesting features when compared to others. Give it a try, and you will see the difference! Instant jsoup How-to provides simple and detailed instructions on how to use the Jsoup library to manipulate HTML content to suit your needs. You will learn the basic aspects of data crawling, as well as the various concepts of Jsoup so you can make the best use of the library to achieve your goals. Instant jsoup How-to will help you learn step-by-step using real-world, practical problems. You will begin by learning several basic topics, such as getting input from a URL, a file, or a string, as well as making use of DOM navigation to search for data. You will then move on to some advanced topics like how to use the CSS selector and how to clean dirty HTML data. HTML data is not always safe, and because of that, you will learn how to sanitize the dirty documents to prevent further XSS attacks. Instant jsoup How-to is a book for every Java developer who wants to learn HTML manipulation quickly and effectively. This book includes the sample source code for you to refer to with a detailed explanation of every feature of the library.
Table of Contents (7 chapters)

Preface

Web services are developing advanced technologies to provide information to third parties through forms such as RSS and Atom or through web service APIs such as SOAP and REST. However, it is inevitable that you will have to scrape HTML content from websites with no built-in web services at some point in your career. That's when you should take a look and enhance your capability of web scraping using one of the most powerful Java web scraping libraries, Jsoup.

What this book covers

Getting input for parser to create an, HTML document object structure.

Extracting data using DOM from the HTML page.

Extracting data using CSS selector from the HTML page.

Transforming HTML elements to create, update, or remove contents inside elements.

Miscellaneous Jsoup options for empowering parsing ability in various ways.

Cleaning dirty HTML documents to transform malformed or buggy XSS into a well-formed document.

Listing all URLs within in an HTML page to practice the first real-world problem.

Listing all images within in an HTML page is a simple solution to crawling all images in a website.

What you need for this book

Software required: Java SDK v6 or above.

Skills required:

  • Java programming

  • Basic network programming

  • Knowledge of HTML and DOM structure

Who this book is for

If you are a Java developer about to make your applications scrape content from some websites and don't have much of an idea on how it works, this book is definitely for you. This book is written as a step-by-step explanation; thus, even a beginner can learn and master Jsoup.

Conventions

In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

Code words in text are shown as follows: "In HTML, the images are usually put under the <img> tag, so the selector to query these images is img[src]."

A block of code is set as follows:

<html>
  <head>
  <title>Section 04: Modify elements' contents</title>
  <body>
    <h1>Jsoup: the HTML parser</h1>
  </body>
</html>

New terms and important words are shown in bold.

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.

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