如何在Java正则表达式匹配中使用IsAlphabetic二进制属性？

Question

我使用此模式检查字符串是否以冒号前面至少2个字母字符开头：

string.matches("^\\p{IsAlphabetic}{2,}:")

但我遇到以下异常：

java.util.regex.PatternSyntaxException: Unknown character property name {Alphabetic} near index 16
    ^\p{IsAlphabetic}{2,}:
    ^
    at java.util.regex.Pattern.error(Pattern.java:1730)
    at java.util.regex.Pattern.charPropertyNodeFor(Pattern.java:2454)
    at java.util.regex.Pattern.family(Pattern.java:2429)
    at java.util.regex.Pattern.sequence(Pattern.java:1848)
    at java.util.regex.Pattern.expr(Pattern.java:1769)
    at java.util.regex.Pattern.compile(Pattern.java:1477)
    at java.util.regex.Pattern.<init>(Pattern.java:1150)
    at java.util.regex.Pattern.compile(Pattern.java:840)
    at java.util.regex.Pattern.matches(Pattern.java:945)
    at java.lang.String.matches(String.java:2102)

即使模式类的规范规定：

Binary properties are specified with the prefix Is, as in IsAlphabetic. The supported binary properties by Pattern are

• Alphabetic
• Ideographic
• Letter
• ...

以及Unicode脚本、块、类别和二进制属性的类部分 列表

\p{IsAlphabetic} An alphabetic character (binary property)

Answer 1

使用Java1.8工作并返回true

String s = "äö:";
System.out.println(s.matches("^\\p{IsAlphanumeric}{2,}:"));

请注意，Java 1.7中可用的表单（Alpha、IsAlpha）不一定包含US-ASCII以外的字符。这将返回false：

String s = "äö:";
System.out.println(s.matches("^\\p{IsAlpha}{2,}:"));

但请注意，这在1.7中起作用，并返回true：

String s = "äö:";
Pattern pat = Pattern.compile( "^\\p{Alpha}{2,}:",
                     Pattern.UNICODE_CHARACTER_CLASS );
Matcher mat = pat.matcher( s );
System.out.println(mat.matches());