Converting from half-width katakana to full-width katakana

Question

I need to convert halfwidth katakana characters to fullwidth characters.

Example:

• String "ｶﾀｶﾅ" (U+FF76 U+FF80 U+FF76 U+FF85)
• Convert to "カタカナ" (U+30AB U+30BF U+30AB U+30CA)

How can I do this in Java?

Answer 1

I think you are talking about converting "half-width Katakana" Unicode code-points to their regular equivalents.

See here for info, including a listing of the relevant code point values:

• https://sites.psu.edu/symbolcodes/languages/asia/japanese/katakanachart/ - scroll all the way down for the half-width codes.

I don't know if there is a recommended way to do it (eg a standard API or 3rd-party library), but you could easily write some code to:

• put the text to a StringBuilder
• iterate the character positions in the builder
  • fetch the character from the builder
  • identify the half-width katakana characters (by doing a range check)
  • map the to full-width equivalents (by adding an offset ... or using a Map )
  • update character in the builder
• Use the contents of the updated builder; eg turn it into a String .

Answer 2

You could try the icu4j library. It supports a number of transliterations , including Halfwidth-Fullwidth and Fullwidth-Halfwidth .

Example:

Transliterator t = Transliterator.getInstance("Halfwidth-Fullwidth");
String result = t.transliterate(original);

Answer 3

Use just standard API (java.text.Normalizer). No need 3rd party solution or dependency.

It converts full-width alphanumeric characters to half-width and half-width katakana to full-width katakana

Normalizer.normalize(text, Normalizer.Form.NFKC)