Handling ASCII character set in Java (I)

7 February 2008

In this post, I will talk about ASCII character set and how to deal with ASCII codes in Java.

ASCII character uses 7 bits for character representation. This means that there are total of 128 characters supported by ASCII set. Point to note is that there are only 93 printable characters in ASCII whose ASCII codes are from 33 till 126.

Java supports all popular character including UTF. But sometimes you only want the input to comprise of ASCII printable characters. This may be useful if your business logic does not allow any other character set.

Lets first see all the printable characters in ASCII character set.

for (int i=33;i<=126;i++)
System.out.println("Code: " + i + " Character: " +(char)i);

Output:

Code: 33 Character: !
Code: 34 Character: "
Code: 35 Character: #
Code: 36 Character: $
Code: 37 Character: %
Code: 38 Character: &
Code: 39 Character: '
Code: 40 Character: (
Code: 41 Character: )
Code: 42 Character: *
Code: 43 Character: +
Code: 44 Character: ,
Code: 45 Character: -
Code: 46 Character: .
Code: 47 Character: /
Code: 48 Character: 0
Code: 49 Character: 1
Code: 50 Character: 2
Code: 51 Character: 3
Code: 52 Character: 4
Code: 53 Character: 5
Code: 54 Character: 6
Code: 55 Character: 7
Code: 56 Character: 8
Code: 57 Character: 9
Code: 58 Character: :
Code: 59 Character: ;
Code: 60 Character: <
Code: 61 Character: =
Code: 62 Character: >
Code: 63 Character: ?
Code: 64 Character: @
Code: 65 Character: A
Code: 66 Character: B
Code: 67 Character: C
Code: 68 Character: D
Code: 69 Character: E
Code: 70 Character: F
Code: 71 Character: G
Code: 72 Character: H
Code: 73 Character: I
Code: 74 Character: J
Code: 75 Character: K
Code: 76 Character: L
Code: 77 Character: M
Code: 78 Character: N
Code: 79 Character: O
Code: 80 Character: P
Code: 81 Character: Q
Code: 82 Character: R
Code: 83 Character: S
Code: 84 Character: T
Code: 85 Character: U
Code: 86 Character: V
Code: 87 Character: W
Code: 88 Character: X
Code: 89 Character: Y
Code: 90 Character: Z
Code: 91 Character: [
Code: 92 Character: \
Code: 93 Character: ]
Code: 94 Character: ^
Code: 95 Character: _
Code: 96 Character: `
Code: 97 Character: a
Code: 98 Character: b
Code: 99 Character: c
Code: 100 Character: d
Code: 101 Character: e
Code: 102 Character: f
Code: 103 Character: g
Code: 104 Character: h
Code: 105 Character: i
Code: 106 Character: j
Code: 107 Character: k
Code: 108 Character: l
Code: 109 Character: m
Code: 110 Character: n
Code: 111 Character: o
Code: 112 Character: p
Code: 113 Character: q
Code: 114 Character: r
Code: 115 Character: s
Code: 116 Character: t
Code: 117 Character: u
Code: 118 Character: v
Code: 119 Character: w
Code: 120 Character: x
Code: 121 Character: y
Code: 122 Character: z
Code: 123 Character: {
Code: 124 Character: |
Code: 125 Character: }
Code: 126 Character: ~

So now we know the printable characters in ASCII character set.
In the next post, I will talk about how to validate the input for valid ASCII characters.

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