Java中获取某种语言的unicode字符

Question

Java 有什么方法可以让我获得特定语言（例如孟加拉语或阿拉伯语）的所有 Unicode 字符吗？

Answer 1

java.lang.Character 类有一个名为 UnicodeBlock 的内部静态类。例如，您可以这样获取阿拉伯语 Unicode 块：

Character.UnicodeBlock block = Character.UnicodeBlock.ARABIC;

通过迭代所有字符（或更准确地说，Unicode 代码点），可以检查每个字符以找到其 Unicode 块：

public static void main(String[] args) {
    Set<Character> arabicChars = findCharactersInUnicodeBlock(Character.UnicodeBlock.ARABIC);
    Set<Character> bengaliChars = findCharactersInUnicodeBlock(Character.UnicodeBlock.BENGALI);
}

private static Set<Character> findCharactersInUnicodeBlock(final Character.UnicodeBlock block) {
    final Set<Character> chars = new HashSet<Character>();
    for (int codePoint = Character.MIN_CODE_POINT; codePoint <= Character.MAX_CODE_POINT; codePoint++) {
        if (block == Character.UnicodeBlock.of(codePoint)) {
            chars.add((char) codePoint);
        }
    }
    return chars;
}

Answer 2

在 1.7 之前，Java 不支持 Unicode 脚本。不过，Java 对 Unicode 属性的支持非常粗略。它基本上停留在 Unicode 千禧年前的化身上。这是一个真正的问题。他们声称他们将通过 JDK7 赶上 Unicode 6，但我还没有看到任何证据表明他们将拥有适当的属性支持。

在 Unicode 6.0 中，总共有 1,051 个代码点算作阿拉伯语，其中 1,020 个代码点位于基本多语言平面中：

% unichars --bmp  '\p{Script=Arabic}' | wc -l
    1020

% unichars -a '\p{Script=Arabic}' | wc -l
    1051

有效的原因是 unichars 程序是用 Perl 编写的，而 Perl 始终具有优秀 Unicode 属性支持。我正在针对 Unicode 6.0 运行它；以前版本的 Unicode 中的数量要少一些。事实上，Unicode 6.0 添加了 17 个新的阿拉伯字符：

 % unichars -a '\p{Script=Arabic}' '\p{Age:6.0}' | wc -l
         17

您不能尝试为此使用块。脚本与块不同。并非给定块中的所有代码点都属于同一脚本。同样重要的是，您经常会发现给定脚本的字符分散在奇怪的块中。

例如，希腊语块中有 18 个非希腊字符：

% unichars '\p{InGreek}' '\P{IsGreek}'ˋ | wc -l
     18

阿拉伯语块中有 13 个非阿拉伯字符：

% unichars '\p{InArabic}' '\P{IsArabic}' | wc -l
     13

另外还有 4 个希腊语块和 4（或 5）个阿拉伯语块：

% uniprops -l | grep 'Block:.*Greek'
Block:Ancient_Greek_Musical_Notation
Block:Ancient_Greek_Numbers
Block:Greek
Block:Greek_And_Coptic
Block:Greek_Extended

% uniprops -l | grep 'Block:.*Arab'
Block:Arabic
Block:Arabic_Presentation_Forms_A
Block:Arabic_Presentation_Forms_B
Block:Arabic_Supplement 
Block:Old_South_Arabian

\p{Block:Greek } 和 \p{Greek_and_Coptic} 是别名，但其余的都是不同的。

但即使你查看了所有这些块，你还是会错过一些。例如：

% unichars '\p{IsGreek}' '[^\p{InAncient_Greek_Musical_Notation}\p{InAncient_Greek_Numbers}\p{InGreek}\p{InGreek_Extended}]' 
 ᴦ  7462 1D26 GREEK LETTER SMALL CAPITAL GAMMA
 ᴧ  7463 1D27 GREEK LETTER SMALL CAPITAL LAMDA
 ᴨ  7464 1D28 GREEK LETTER SMALL CAPITAL PI
 ᴩ  7465 1D29 GREEK LETTER SMALL CAPITAL RHO
 ᴪ  7466 1D2A GREEK LETTER SMALL CAPITAL PSI
 ᵝ  7517 1D5D MODIFIER LETTER SMALL BETA
 ᵞ  7518 1D5E MODIFIER LETTER SMALL GREEK GAMMA
 ᵟ  7519 1D5F MODIFIER LETTER SMALL DELTA
 ᵠ  7520 1D60 MODIFIER LETTER SMALL GREEK PHI
 ᵡ  7521 1D61 MODIFIER LETTER SMALL CHI
 ᵦ  7526 1D66 GREEK SUBSCRIPT SMALL LETTER BETA
 ᵧ  7527 1D67 GREEK SUBSCRIPT SMALL LETTER GAMMA
 ᵨ  7528 1D68 GREEK SUBSCRIPT SMALL LETTER RHO
 ᵩ  7529 1D69 GREEK SUBSCRIPT SMALL LETTER PHI
 ᵪ  7530 1D6A GREEK SUBSCRIPT SMALL LETTER CHI
 ᶿ  7615 1DBF MODIFIER LETTER SMALL THETA
 Ω  8486 2126 OHM SIGN

看到问题了吗？

顺便说一句，您使用 uniprops 不仅仅是列出所有可能的属性。它还可以为您提供任何给定代码点的属性：

% uniprops -a 1dbf 9e6 NEL Greek:Omicron
U+1DBF <ᶿ> \N{ MODIFIER LETTER SMALL THETA }:
    \w \pL \p{L_} \p{Lm}
    All Any Alnum Alpha Alphabetic Assigned Greek Is_Greek InPhoneticExtensionsSupplement Case_Ignorable CI Cased Changes_When_NFKC_Casefolded CWKCF L Lm Gr_Base Grapheme_Base Graph GrBase Grek ID_Continue IDC ID_Start IDS Letter L_ Modifier_Letter Lower Lowercase Print Word XID_Continue XIDC XID_Start XIDS
    Age:4.1 Bidi_Class:L Bidi_Class=Left_To_Right Bidi_Class:Left_To_Right Bc=L Block:Phonetic_Extensions_Supplement Canonical_Combining_Class:0 Canonical_Combining_Class=Not_Reordered Canonical_Combining_Class:Not_Reordered Ccc=NR Canonical_Combining_Class:NR Decomposition_Type:Non_Canon Decomposition_Type=Non_Canonical
       Decomposition_Type:Non_Canonical Dt=NonCanon Decomposition_Type:Sup Decomposition_Type=Super Decomposition_Type:Super Dt=Sup East_Asian_Width=Neutral East_Asian_Width:Neutral Grapheme_Cluster_Break:Other GCB=XX Grapheme_Cluster_Break:XX Grapheme_Cluster_Break=Other Script=Greek Hangul_Syllable_Type:NA
       Hangul_Syllable_Type=Not_Applicable Hangul_Syllable_Type:Not_Applicable Hst=NA Joining_Group:No_Joining_Group Jg=NoJoiningGroup Joining_Type:Non_Joining Jt=U Joining_Type:U Joining_Type=Non_Joining Line_Break:AL Line_Break=Alphabetic Line_Break:Alphabetic Lb=AL Numeric_Type:None Nt=None Numeric_Value:NaN Nv=NaN Present_In:4.1
       In=4.1 Present_In:5.0 In=5.0 Present_In:5.1 In=5.1 Present_In:5.2 In=5.2 Script:Greek Sc=Grek Script:Grek Sentence_Break:LO Sentence_Break=Lower Sentence_Break:Lower SB=LO Word_Break:ALetter WB=LE Word_Break:LE Word_Break=ALetter
U+09E6 <০> \N{ BENGALI DIGIT ZERO }:
    \w \d \pN \p{Nd}
    All Any Alnum Assigned Beng Bengali InBengali Is_Bengali Decimal_Number Digit Nd N Gr_Base Grapheme_Base Graph GrBase ID_Continue IDC Number Print Word XID_Continue XIDC
    Age:1.1 Script=Bengali Block=Bengali Bidi_Class:L Bidi_Class=Left_To_Right Bidi_Class:Left_To_Right Bc=L Block:Bengali Canonical_Combining_Class:0 Canonical_Combining_Class=Not_Reordered Canonical_Combining_Class:Not_Reordered Ccc=NR Canonical_Combining_Class:NR Decomposition_Type:None Dt=None East_Asian_Width=Neutral
       East_Asian_Width:Neutral Grapheme_Cluster_Break:Other GCB=XX Grapheme_Cluster_Break:XX Grapheme_Cluster_Break=Other Hangul_Syllable_Type:NA Hangul_Syllable_Type=Not_Applicable Hangul_Syllable_Type:Not_Applicable Hst=NA Joining_Group:No_Joining_Group Jg=NoJoiningGroup Joining_Type:Non_Joining Jt=U Joining_Type:U
       Joining_Type=Non_Joining Line_Break:NU Line_Break=Numeric Line_Break:Numeric Lb=NU Numeric_Type:De Numeric_Type=Decimal Numeric_Type:Decimal Nt=De Numeric_Value:0 Nv=0 Present_In:1.1 Age=1.1 In=1.1 Present_In:2.0 In=2.0 Present_In:2.1 In=2.1 Present_In:3.0 In=3.0 Present_In:3.1 In=3.1 Present_In:3.2 In=3.2 Present_In:4.0 In=4.0
       Present_In:4.1 In=4.1 Present_In:5.0 In=5.0 Present_In:5.1 In=5.1 Present_In:5.2 In=5.2 Script:Beng Script:Bengali Sc=Beng Sentence_Break:NU Sentence_Break=Numeric Sentence_Break:Numeric SB=NU Word_Break:NU Word_Break=Numeric Word_Break:Numeric WB=NU
U+0085 <U+0085> \N{ NEXT LINE (NEL) }:
    \s \v \R \pC \p{Cc}
    All Any Assigned InLatin1 C Other Cc Cntrl Common Zyyy Control Pat_WS Pattern_White_Space PatWS Space SpacePerl VertSpace White_Space WSpace
    Age:1.1 Bidi_Class:B Bidi_Class=Paragraph_Separator Bidi_Class:Paragraph_Separator Bc=B Block:Latin_1 Block=Latin_1_Supplement Block:Latin_1_Supplement Blk=Latin1 Canonical_Combining_Class:0 Canonical_Combining_Class=Not_Reordered Canonical_Combining_Class:Not_Reordered Ccc=NR Canonical_Combining_Class:NR Script=Common
       Decomposition_Type:None Dt=None East_Asian_Width=Neutral East_Asian_Width:Neutral Grapheme_Cluster_Break:CN Grapheme_Cluster_Break=Control Grapheme_Cluster_Break:Control GCB=CN Hangul_Syllable_Type:NA Hangul_Syllable_Type=Not_Applicable Hangul_Syllable_Type:Not_Applicable Hst=NA Joining_Group:No_Joining_Group Jg=NoJoiningGroup
       Joining_Type:Non_Joining Jt=U Joining_Type:U Joining_Type=Non_Joining Line_Break:Next_Line Lb=NL Line_Break:NL Line_Break=Next_Line Numeric_Type:None Nt=None Numeric_Value:NaN Nv=NaN Present_In:1.1 Age=1.1 In=1.1 Present_In:2.0 In=2.0 Present_In:2.1 In=2.1 Present_In:3.0 In=3.0 Present_In:3.1 In=3.1 Present_In:3.2 In=3.2
       Present_In:4.0 In=4.0 Present_In:4.1 In=4.1 Present_In:5.0 In=5.0 Present_In:5.1 In=5.1 Present_In:5.2 In=5.2 Script:Common Sc=Zyyy Script:Zyyy Sentence_Break:SE Sentence_Break=Sep Sentence_Break:Sep SB=SE Word_Break:Newline WB=NL Word_Break:NL Word_Break=Newline
U+039F <Ο> \N{ GREEK CAPITAL LETTER OMICRON }:
    \w \pL \p{LC} \p{L_} \p{L&} \p{Lu}
    All Any Alnum Alpha Alphabetic Assigned Greek Is_Greek InGreek Cased Cased_Letter LC Changes_When_Casefolded CWCF Changes_When_Casemapped CWCM Changes_When_Lowercased CWL Changes_When_NFKC_Casefolded CWKCF Lu L Gr_Base Grapheme_Base Graph GrBase Grek Greek_And_Coptic ID_Continue IDC ID_Start IDS Letter L_ Uppercase_Letter Print Upper
       Uppercase Word XID_Continue XIDC XID_Start XIDS
    Age:1.1 Bidi_Class:L Bidi_Class=Left_To_Right Bidi_Class:Left_To_Right Bc=L Block:Greek Block=Greek_And_Coptic Block:Greek_And_Coptic Blk=Greek Canonical_Combining_Class:0 Canonical_Combining_Class=Not_Reordered Canonical_Combining_Class:Not_Reordered Ccc=NR Canonical_Combining_Class:NR Decomposition_Type:None Dt=None
       East_Asian_Width:A East_Asian_Width=Ambiguous East_Asian_Width:Ambiguous Ea=A Grapheme_Cluster_Break:Other GCB=XX Grapheme_Cluster_Break:XX Grapheme_Cluster_Break=Other Script=Greek Hangul_Syllable_Type:NA Hangul_Syllable_Type=Not_Applicable Hangul_Syllable_Type:Not_Applicable Hst=NA Joining_Group:No_Joining_Group Jg=NoJoiningGroup
       Joining_Type:Non_Joining Jt=U Joining_Type:U Joining_Type=Non_Joining Line_Break:AL Line_Break=Alphabetic Line_Break:Alphabetic Lb=AL Numeric_Type:None Nt=None Numeric_Value:NaN Nv=NaN Present_In:1.1 Age=1.1 In=1.1 Present_In:2.0 In=2.0 Present_In:2.1 In=2.1 Present_In:3.0 In=3.0 Present_In:3.1 In=3.1 Present_In:3.2 In=3.2
       Present_In:4.0 In=4.0 Present_In:4.1 In=4.1 Present_In:5.0 In=5.0 Present_In:5.1 In=5.1 Present_In:5.2 In=5.2 Script:Greek Sc=Grek Script:Grek Sentence_Break:UP Sentence_Break=Upper Sentence_Break:Upper SB=UP Word_Break:ALetter WB=LE Word_Break:LE Word_Break=ALetter

如果您发现它们有用，您可以下载 uniprops 和 unichars 节目。该组中有第三个，uninames。所有内容均附有说明和示例。

即使其中一些属性在 Java 中还不能直接使用，如果您愿意，也可以使用 Perl 生成 Java 代码；我自己也经常这么做。 :)