非 BMP 平面字符的 Unicode 转义序列

Question

["

In java,<\/i>

char ch = '\u00A5'; // '¥'

Answer 1

You cannot do that with a single char constant, since a char is a UTF-16 code unit. You have to use a String constant, such as:

final String s = "\uXXXX\uYYYY";

where XXXX is the high surrogate and YYYY is the low surrogate.

Another solution is to use an int to store the code point; you can then use Character.toChars() to obtain a char[] out of it:

final int codePoint = 0x1f4ae; // for instance
final char[] toChars = Charater.toChars(codePoint);

Depending on what you use, you may also append code points directly (a StringBuilder has a method for that, for instance).

Answer 2

To avoid writing surrogates pair for non-BMP chars and obtaining a String from a code point there are several methods.

String test1 = new String(new int[] { 0x1f4ae }, 0, 1);
String test2 = String.valueOf(Character.toChars(0x1f4ae));
String test3 = Character.toString(0x1f4ae):