问题
I have a list with some Belgian cities with diacritic characters: (Liège, Quiévrain, Franière, etc.) and I would like to transform these special characters to compare with a list containing the same names in upper case, but without the diacritical marks (LIEGE, QUIEVRAIN, FRANIERE)
What i first tried to do was to use the upper case:
LIEGE.contentEqual(Liège.toUpperCase()) but that doesn't fit because the Upper case of Liège is LIÈGE and not LIEGE.
I have some complicated ideas like replacing each character, but that sounds stupid and a long process.
Any ideas on how to do this in a smart way?
回答1:
Check out this method in Java
private static final String PLAIN_ASCII = "AaEeIiOoUu" // grave
+ "AaEeIiOoUuYy" // acute
+ "AaEeIiOoUuYy" // circumflex
+ "AaOoNn" // tilde
+ "AaEeIiOoUuYy" // umlaut
+ "Aa" // ring
+ "Cc" // cedilla
+ "OoUu" // double acute
;
private static final String UNICODE = "\u00C0\u00E0\u00C8\u00E8\u00CC\u00EC\u00D2\u00F2\u00D9\u00F9"
+ "\u00C1\u00E1\u00C9\u00E9\u00CD\u00ED\u00D3\u00F3\u00DA\u00FA\u00DD\u00FD"
+ "\u00C2\u00E2\u00CA\u00EA\u00CE\u00EE\u00D4\u00F4\u00DB\u00FB\u0176\u0177"
+ "\u00C3\u00E3\u00D5\u00F5\u00D1\u00F1"
+ "\u00C4\u00E4\u00CB\u00EB\u00CF\u00EF\u00D6\u00F6\u00DC\u00FC\u0178\u00FF"
+ "\u00C5\u00E5" + "\u00C7\u00E7" + "\u0150\u0151\u0170\u0171";
/**
* remove accented from a string and replace with ascii equivalent
*/
public static String removeAccents(String s) {
if (s == null)
return null;
StringBuilder sb = new StringBuilder(s.length());
int n = s.length();
int pos = -1;
char c;
boolean found = false;
for (int i = 0; i < n; i++) {
pos = -1;
c = s.charAt(i);
pos = (c <= 126) ? -1 : UNICODE.indexOf(c);
if (pos > -1) {
found = true;
sb.append(PLAIN_ASCII.charAt(pos));
} else {
sb.append(c);
}
}
if (!found) {
return s;
} else {
return sb.toString();
}
}
回答2:
As of Java 6, you can use java.text.Normalizer:
public String unaccent(String s) {
String normalized = Normalizer.normalize(s, Normalizer.Form.NFD);
return normalized.replaceAll("[^\\p{ASCII}]", "");
}
Note that in Java 5 there is also a sun.text.Normalizer, but its use is strongly discouraged since it's part of Sun's proprietary API and has been removed in Java 6.
回答3:
This is the simplest solution I've found so far and it works perfectly in our applications.
Normalizer.normalize(string, Normalizer.Form.NFD).replaceAll("\\p{InCombiningDiacriticalMarks}+", "");
But I don't know if the Normalizer is available on the Android platform.
回答4:
If you still need that for Android API 8 or lower (Android 2.2, Java 1.5) where you don't have Normalizer class, here's my code, I think better to modify than Pentium10 answer:
public class StringAccentRemover {
@SuppressWarnings("serial")
private static final HashMap<Character, Character> accents = new HashMap<Character, Character>(){
{
put('Ą', 'A');
put('Ę', 'E');
put('Ć', 'C');
put('Ł', 'L');
put('Ń', 'N');
put('Ó', 'O');
put('Ś', 'S');
put('Ż', 'Z');
put('Ź', 'Z');
put('ą', 'a');
put('ę', 'e');
put('ć', 'c');
put('ł', 'l');
put('ń', 'n');
put('ó', 'o');
put('ś', 's');
put('ż', 'z');
put('ź', 'z');
}
};
/**
* remove accented from a string and replace with ascii equivalent
*/
public static String removeAccents(String s) {
char[] result = s.toCharArray();
for(int i=0; i<result.length; i++) {
Character replacement = accents.get(result[i]);
if (replacement!=null) result[i] = replacement;
}
return new String(result);
}
}
回答5:
The Collator class is a good way to do it (see corresponding javadoc). Here is a unit test that shows how to use it :
import static org.junit.Assert.assertEquals;
import java.text.Collator;
import java.util.Locale;
import org.junit.Test;
public class CollatorTest {
@Test public void liege() throws Exception {
Collator compareOperator = Collator.getInstance(Locale.FRENCH);
compareOperator.setStrength(Collator.PRIMARY);
assertEquals(0, compareOperator.compare("Liege", "Liege")); // no accent
assertEquals(0, compareOperator.compare("Liège", "Liege")); // with accent
assertEquals(0, compareOperator.compare("LIEGE", "Liege")); // case insensitive
assertEquals(0, compareOperator.compare("LIEGE", "Liège")); // case insensitive with accent
assertEquals(1, compareOperator.compare("Liege", "Bruxelles"));
assertEquals(-1, compareOperator.compare("Bruxelles", "Liege"));
}
}
EDIT : sorry to see my answer did not meet your needs ; maybe it's beause I've presented it as unit test ? Is this ok for you ? I personnaly find it better because it's short and it uses the SDK (no need for String replacement)
Collator compareOperator = Collator.getInstance(Locale.FRENCH);
compareOperator.setStrength(Collator.PRIMARY);
if (compareOperator.compare("Liège", "Liege") == 0) {
// if we are here, then it's the "same" String
}
hope this helps
回答6:
I don't know if it is avaible on Android but on the JVM, you should not reimplement it in your project and reuse already existing code: just use org.apache.commons.lang3.StringUtils#stripAccents
回答7:
For those looking for a clean java solution, use apache commons:
StringUtils.stripAccents("Liège").toUpperCase();
this will return
LIEGE
回答8:
Since class Normalizer is not supported in Froyo or previous Android versions, I have combined this and this (which I both voted up), and optimized it, obtaining a couple of helper methods. Method unaccentify simply converts diacritic chars to plain chars, while method slugify generates a slug for the input string. Hope it can be useful to someone. Here is the source code:
import java.util.Arrays;
import java.util.Locale;
import java.util.regex.Pattern;
public class SlugFroyo {
private static final Pattern STRANGE = Pattern.compile("[^a-zA-Z0-9-]");
private static final Pattern WHITESPACE = Pattern.compile("[\\s]");
private static final String DIACRITIC_CHARS = "\u00C0\u00E0\u00C8\u00E8\u00CC\u00EC\u00D2\u00F2\u00D9\u00F9"
+ "\u00C1\u00E1\u00C9\u00E9\u00CD\u00ED\u00D3\u00F3\u00DA\u00FA\u00DD\u00FD"
+ "\u00C2\u00E2\u00CA\u00EA\u00CE\u00EE\u00D4\u00F4\u00DB\u00FB\u0176\u0177"
+ "\u00C3\u00E3\u00D5\u00F5\u00D1\u00F1"
+ "\u00C4\u00E4\u00CB\u00EB\u00CF\u00EF\u00D6\u00F6\u00DC\u00FC\u0178\u00FF"
+ "\u00C5\u00E5" + "\u00C7\u00E7" + "\u0150\u0151\u0170\u0171";
private static final String PLAIN_CHARS = "AaEeIiOoUu" // grave
+ "AaEeIiOoUuYy" // acute
+ "AaEeIiOoUuYy" // circumflex
+ "AaOoNn" // tilde
+ "AaEeIiOoUuYy" // umlaut
+ "Aa" // ring
+ "Cc" // cedilla
+ "OoUu"; // double acute
private static char[] lookup = new char[0x180];
static {
Arrays.fill(lookup, (char) 0);
for (int i = 0; i < DIACRITIC_CHARS.length(); i++)
lookup[DIACRITIC_CHARS.charAt(i)] = PLAIN_CHARS.charAt(i);
}
public static String slugify(String s) {
String nowhitespace = WHITESPACE.matcher(s).replaceAll("-");
String unaccented = unaccentify(nowhitespace);
String slug = STRANGE.matcher(unaccented).replaceAll("");
return slug.toLowerCase(Locale.ENGLISH);
}
public static String unaccentify(String s) {
StringBuilder sb = new StringBuilder(s);
for (int i = 0; i < sb.length(); i++) {
char c = sb.charAt(i);
if (c > 126 && c < lookup.length) {
char replacement = lookup[c];
if (replacement > 0)
sb.setCharAt(i, replacement);
}
}
return sb.toString();
}
}
来源：https://stackoverflow.com/questions/3211974/ignoring-diacritic-characters-when-comparing-words-with-special-characters-%c3%a9-%c3%a8