Java Cookbook

Converting Between Unicode Characters and Strings

Problem

You want to convert between Unicode characters and Strings.

Solution

Since both Java chars and Unicode characters are 16 bits in width, a char can hold any Unicode character. The charAt( ) method of String returns a Unicode character. The StringBuffer append( ) method has a form that accepts a char. Since char is an integer type, you can even do arithmetic on chars, though this is not necessary as frequently as in, say, C. Nor is it often recommended, since the Character class provides the methods for which these operations were normally used in languages such as C. Here is a program that uses arithmetic on chars to control a loop, and also appends the characters into a StringBuffer (see Section 3.4):

/**
 * Conversion between Unicode characters and bytes
 */
public class UnicodeChars {
    public static void main(String[] argv) {
        StringBuffer b = new StringBuffer(  );
        for (char c = 'a'; c<'d'; c++) {
            b.append(c);
        }
        b.append('\u00a5');    // Japanese Yen symbol
        b.append('\u01FC');    // Roman AE with acute accent
        b.append('\u0391');    // GREEK Capital Alpha
        b.append('\u03A9');    // GREEK Capital Omega

        for (int i=0; i<b.length(  ); i++) {
            System.out.println("Character #" + i + " is " + b.charAt(i));
        }
        System.out.println("Accumulated characters are " + b);
    }
}

When you run it, the expected results are printed for the ASCII characters. On my Unix system, the default fonts don’t include all the additional characters, so they are either omitted ...