Book Image

Java 9 Regular Expressions

By : Anubhava Srivastava
Book Image

Java 9 Regular Expressions

By: Anubhava Srivastava

Overview of this book

Regular expressions are a powerful tool in the programmer's toolbox and allow pattern matching. They are also used for manipulating text and data. This book will provide you with the know-how (and practical examples) to solve real-world problems using regex in Java. You will begin by discovering what regular expressions are and how they work with Java. This easy-to-follow guide is a great place from which to familiarize yourself with the core concepts of regular expressions and to master its implementation with the features of Java 9. You will learn how to match, extract, and transform text by matching specific words, characters, and patterns. You will learn when and where to apply the methods for finding patterns in digits, letters, Unicode characters, and string literals. Going forward, you will learn to use zero-length assertions and lookarounds, parsing the source code, and processing the log files. Finally, you will master tips, tricks, and best practices in regex with Java.
Table of Contents (15 chapters)
Title page
About the Author
About the Reviewer
Customer Feedback
Free Chapter
Getting Started with Regular Expressions

Using regular expressions in Java Scanner API

A scanner is a utility class used for parsing the input text and breaking the input into tokens of various types, such as Boolean, int, float, double, long, and so on. It generates tokens of various types using regular expression-based delimiters. The default delimiter is a whitespace. Using the Scanner API, we can generate tokens of all the primitive types in addition to string tokens.

The String, Pattern, and Matcher classes are able to parse the input and generate tokens of the String type only, but the Scanner class is very useful for checking and generating tokens of different types from the input source. The Scanner instance can be constructed using the File, InputStream, Path, Readable, ReadableByteChannel, and String arguments.


Pattern and Matcher will be covered in detail in Chapter 5, Introduction to Java Regular Expression APIs - Pattern and Matcher Classes.

There are many methods in the scanner that support regular expressions...