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.
Note
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...