一种快速安全的方式

public static String removeDiacritics(String str) {
    if (str == null)
        return null;
    if (str.isEmpty())
        return "";
    
    int len = str.length();
    StringBuilder sb
        = new StringBuilder(len);
    
    //iterate string codepoints
    for (int i = 0; i < len; ) {
        int codePoint = str.codePointAt(i);
        int charCount
            = Character.charCount(codePoint);
        
        if (charCount > 1) {
            for (int j = 0; j < charCount; j++)
                sb.append(str.charAt(i + j));
            i += charCount;
            continue;
        }
        else if (codePoint <= 127) {
            sb.append((char)codePoint);
            i++;
            continue;
        }
        
        sb.append(
            java.text.Normalizer
                .normalize(
                    Character.toString((char)codePoint),
                    java.text.Normalizer.Form.NFD)
                        .charAt(0));
        i++;
    }
    
    return sb.toString();
}

如果你没有库，使用regex和Normalizer的最好方法之一是:

    public String flattenToAscii(String s) {
                if(s == null || s.trim().length() == 0)
                        return "";
                return Normalizer.normalize(s, Normalizer.Form.NFD).replaceAll("[\u0300-\u036F]", "");
}

这比replaceAll("[^\p{ASCII}]"， ""))更有效，而且如果你不需要变音符符(就像你的例子一样)。

否则，您必须使用p{ASCII}模式。

的问候。

从java.text.Normalizer开始。

string = Normalizer.normalize(string, Normalizer.Form.NFD);
// or Normalizer.Form.NFKD for a more "compatible" deconstruction 

这将从大多数字符中分离所有重音符号。然后，你只需要将每个字符与字母进行比较，并排除那些不是字母的字符。

string = string.replaceAll("[^\\p{ASCII}]", "");

如果你的文本是Unicode，你应该使用这个:

string = string.replaceAll("\\p{M}", "");

对于Unicode， \\P{M}匹配基本字形，\\P{M}(小写)匹配每个重音。

感谢GarretWilson提供的指针和正则表达式.info提供的Unicode指南。

需要注意的是，Normalizer本身不足以删除变音符。例如，下面的代码不会将重音的é替换为不重音的e:

import static java.text.Normalizer.normalize;
import static java.text.Normalizer.Form.*;

public class T {
  public static void main( final String[] args ) {
    final var text = "Brévis";

    System.out.println(
      normalize( text, NFD ) + " " + 
      normalize( text, NFC ) + " " + 
      normalize( text, NFKD ) + " " + 
      normalize( text, NFKC )
    );
  }
}

根据语言的不同，这些可能不被认为是重音(改变字母的发音)，而是变音符符号

https://en.wikipedia.org/wiki/Diacritic#Languages_with_letters_containing_diacritics

“波斯尼亚语和克罗地亚语都有符号“č”、“ovic”、“đ”、“š”和“ž”，这些符号被认为是单独的字母，在字典和其他按字母顺序排列单词的语境中都是这样列出的。”

删除它们可能会从本质上改变单词的意思，或者将字母变成完全不同的字母。

我认为最好的解决方案是将每个char转换为HEX，并用另一个HEX替换它。因为有两种Unicode类型:

Composite Unicode
Precomposed Unicode

例如，Composite Unicode编写的“Ồ”不同于precompose Unicode编写的“Ồ”。您可以复制我的示例字符并转换它们以查看差异。

In Composite Unicode, "Ồ" is combined from 2 char: Ô (U+00d4) and ̀ (U+0300)
In Precomposed Unicode, "Ồ" is single char (U+1ED2)

我为一些银行开发了这个功能，以便在将信息发送到核心银行(通常不支持Unicode)之前转换信息，当最终用户使用多种Unicode类型输入数据时，就会遇到这个问题。所以我认为，转换为HEX并替换它是最可靠的方法。

我也遇到过与字符串相等性检查相关的相同问题，比较字符串中的一个 ASCII字符码128-255。

i.e., Non-breaking space - [Hex - A0] Space [Hex - 20]. To show Non-breaking space over HTML. I have used the following spacing entities. Their character and its bytes are like &emsp is very wide space[ ]{-30, -128, -125}, &ensp is somewhat wide space[ ]{-30, -128, -126}, &thinsp is narrow space[ ]{32} , Non HTML Space {} String s1 = "My Sample Space Data", s2 = "My Sample Space Data"; System.out.format("S1: %s\n", java.util.Arrays.toString(s1.getBytes())); System.out.format("S2: %s\n", java.util.Arrays.toString(s2.getBytes())); Output in Bytes: S1: [77, 121, 32, 83, 97, 109, 112, 108, 101, 32, 83, 112, 97, 99, 101, 32, 68, 97, 116, 97] S2: [77, 121, -30, -128, -125, 83, 97, 109, 112, 108, 101, -30, -128, -125, 83, 112, 97, 99, 101, -30, -128, -125, 68, 97, 116, 97]

对于不同的空格及其字节码使用下面的代码:wiki for List_of_Unicode_characters

String spacing_entities = "very wide space,narrow space,regular space,invisible separator";
System.out.println("Space String :"+ spacing_entities);
byte[] byteArray = 
    // spacing_entities.getBytes( Charset.forName("UTF-8") );
    // Charset.forName("UTF-8").encode( s2 ).array();
    {-30, -128, -125, 44, -30, -128, -126, 44, 32, 44, -62, -96};
System.out.println("Bytes:"+ Arrays.toString( byteArray ) );
try {
    System.out.format("Bytes to String[%S] \n ", new String(byteArray, "UTF-8"));
} catch (UnsupportedEncodingException e) {
    e.printStackTrace();
}

➩ ASCII transliterations of Unicode string for Java. unidecode String initials = Unidecode.decode( s2 ); ➩ using Guava: Google Core Libraries for Java. String replaceFrom = CharMatcher.WHITESPACE.replaceFrom( s2, " " ); For URL encode for the space use Guava laibrary. String encodedString = UrlEscapers.urlFragmentEscaper().escape(inputString); ➩ To overcome this problem used String.replaceAll() with some RegularExpression. // \p{Z} or \p{Separator}: any kind of whitespace or invisible separator. s2 = s2.replaceAll("\\p{Zs}", " "); s2 = s2.replaceAll("[^\\p{ASCII}]", " "); s2 = s2.replaceAll(" ", " "); ➩ Using java.text.Normalizer.Form. This enum provides constants of the four Unicode normalization forms that are described in Unicode Standard Annex #15 — Unicode Normalization Forms and two methods to access them. s2 = Normalizer.normalize(s2, Normalizer.Form.NFKC);

测试字符串和输出的不同方法，如➩Unidecode, Normalizer, StringUtils。

String strUni = "Tĥïŝ ĩš â fůňķŷ Šťŕĭńġ Æ,Ø,Ð,ß";

// This is a funky String AE,O,D,ss
String initials = Unidecode.decode( strUni );

// Following Produce this o/p: Tĥïŝ ĩš â fůňķŷ Šťŕĭńġ Æ,Ø,Ð,ß
String temp = Normalizer.normalize(strUni, Normalizer.Form.NFD);
Pattern pattern = Pattern.compile("\\p{InCombiningDiacriticalMarks}+");
temp = pattern.matcher(temp).replaceAll("");

String input = org.apache.commons.lang3.StringUtils.stripAccents( strUni );

使用unidcode是最好的选择，我的最终代码如下所示。

public static void main(String[] args) {
    String s1 = "My Sample Space Data", s2 = "My Sample Space Data";
    String initials = Unidecode.decode( s2 );
    if( s1.equals(s2)) { //[ , ] %A0 - %2C - %20 « http://www.ascii-code.com/
        System.out.println("Equal Unicode Strings");
    } else if( s1.equals( initials ) ) {
        System.out.println("Equal Non Unicode Strings");
    } else {
        System.out.println("Not Equal");
    }

}