复习Java核心技术——卷1，第3章，Code Point
趁着国庆节放假，好好复习一下Java核心技术这本好书。/** * 实验表明，GBK比UTF-8所需要的codepoint更多，和UTF-16差不多。 * 一个代码点(code point)可能有一到两个代码单元(code unit) * @author Roy Zhang * */public class TestCodePoint{ public static void main(String[] args) { String greeting = "Hello★"; int n = greeting.length(); System.out.println(n); // is 5. int cpCount = greeting.codePointCount(0, greeting.length()); System.out.println(cpCount); // is 5. char first = greeting.charAt(0); System.out.println(first); // is H char last = greeting.charAt(greeting.length() - 1); System.out.println(last); // UTF-16 and GBK will show ★ for (int i = 0; i < greeting.codePointCount(0, greeting.length()); i++) { int index = greeting.offsetByCodePoints(0, i); int cp = greeting.codePointAt(index); System.out.println(cp);// they are: 72, 101, 108, 108, 111, 9733 } for (int i = 0; i < greeting.codePointCount(0, greeting.length()); ) { int cp = greeting.codePointAt(i); System.out.println(greeting.charAt(i));// they are: H, e, l, l, o, ★ if (Character.isSupplementaryCodePoint(cp)) { // It does not work. i = i + 2; } else { i++; } } }}
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