Java Reference
In-Depth Information
Display 10.6
Methods in the Class
Scanner
(part 1 of 4)
Scanner
is in the
java.util
package.
public
Scanner(InputStream streamObject)
There is no constructor that accepts a file name as an argument. If you want to create a stream
using a file name, you can use
new
Scanner(
new
FileInputStream(
File_Name
))
When used in this way, the
FileInputStream
constructor, and thus the
Scanner
constructor
invocation, can throw a
FileNotFoundException
, which is a kind of
IOException
.
To create a stream connected to the keyboard, use
new
Scanner(System.in)
public
Scanner(File fileObject)
The
File
class will be covered in the section entitled “The
File
Class,” later in this chapter. We
discuss it here so that you will have a more complete reference in this display, but you can ignore
this entry until after you have read that section.
If you want to create a stream using a file name, you can use
new
Scanner(
new
File(
File_Name
))
public int
nextInt()
Returns the next token as an
int
, provided the next token is a well-formed string representation of
an
int
.
Throws a
NoSuchElementException
if there are no more tokens.
Throws an
InputMismatchException
if the next token is not a well-formed string representation
of an
int
.
Throws an
IllegalStateException
if the
Scanner
stream is closed.
public boolean
hasNextInt()
Returns
true
if the next token is a well-formed string representation of an
int
; otherwise returns
false
.
Throws an
IllegalStateException
if the
Scanner
stream is closed.
public long
nextLong()
Returns the next token as a
long
, provided the next token is a well-formed string representation of
a
long
.
Throws a
NoSuchElementException
if there are no more tokens.
Throws an
InputMismatchException
if the next token is not a well-formed string representation
of a
long
.
Throws an
IllegalStateException
if the
Scanner
stream is closed.
(continued)
