使用Java實現(xiàn)查找并移除字符串中的Emoji

更新時間：2024年03月14日 08:19:48 作者：LetterZ

Emoji 實際上是 UTF-8 (Unicode) 字符集上的特殊字符,這篇文章主要介紹了如何使用Java實現(xiàn)查找并移除字符串中的Emoji,感興趣的可以了解下

一、基礎(chǔ)知識

Emoji 實際上是 UTF-8 (Unicode) 字符集上的特殊字符，多數(shù)基本 Emoji 都被分配到 Unicode 編碼表 1 號平面的 U+1F300–1F6FF 和 U+1F900–1FAFF 兩個區(qū)域，由2個字符組成。
膚色修飾：大多數(shù)與人相關(guān)的 Emoji 默認是黃色的，所以后來引入了五個新碼點作為修飾符：U+1F3FB、U+1F3FC、U+1F3FD、U+1F3FE、U+1F3FF。膚色修飾符追加到現(xiàn)有的 Emoji 后形成新的樣式： U+1F44B(?? ) + U+1F3FD= ????
符號變體或組合：一個普通的字后連接一個或多個變體、組合標識(字符)，組合形成的 Emoji ： U+25C0+U+FE0F= ?? U+27A1+U+FE0F= ?? 1+U+FE0F+U+20E3= 1??
國旗：每個國旗由2個地區(qū)標識符組合而成，地區(qū)標識符的對應(yīng)碼點范圍為U+1F1E6~U+1F1FF，等同于2個指定范圍的普通 Emoji 字符組成。 U+1F1E8+U+1F1F3= ????
零寬度連接符（ZWJ）：多個基礎(chǔ) Emoji 通過零寬度連接符（U+200D）形成的復(fù)雜 Emoji： ??+U+200D+??= ??‍?? ??+U+200D+??‍+U+200D+??= ??‍??‍?? ??+U+200D+??‍+U+200D+??+U+200D+??= ??‍??‍??‍??
序列：一個基礎(chǔ) Emoji 加上多個標簽字符 (U+E0020~ U+E007F )并以 Tag Cancel(U+E007)結(jié)尾，組合形成一個復(fù)雜 Emoji： U+1F3F4(??) +U+E0067+U+E0062+U+E0065+U+E006E+U+E0067+U+E007F= ??????????????
特殊符號：特殊符號只有1個字符，有些符號在某些環(huán)境下會被當(dāng)做Emoj處理：?、?、?;

Unicode 只是約定了碼點到 emoji 的映射關(guān)系，并沒有約定 Emoji 圖形，每個 Emoji 字體文件可以按照自己的想法設(shè)計 Emoji。

二、解決方案

除了一些特殊符號形式的 Emoji，其他Emoji至少有2個字符，所以先根據(jù)第二個字符類型判斷是否為Emoji，使用Character.UnicodeBlock.of和Character.getType方法判定每個字符的類型。

通過第二個字符類型判斷當(dāng)前2個字符為 Emoji 后： 1）判斷是否有后續(xù)修飾 2）判斷處理國旗類型；判斷處理膚色修飾；判斷處理 Emoji 序列標簽；判斷處理零寬度連接符；判斷處理連續(xù)變體、組合標識；按照普通 Emoji 處理；

處理單字符的特殊符號，這一類型內(nèi)有的屬于 Emoji，有的不是，目前全部簡單的按照普通 Emoji 處理；

三、完整代碼

package com.zpf.tool;

import java.util.List;

public class EmojiUtil {

    public static boolean isEmojiNationalFlag(int codePoint) {
        return codePoint >= 127462 && codePoint <= 127487;
    }

    // String str = new String(new int[]{0x1F44B, 0x1F3FD}, 0, 2);
    public static boolean isEmojiSkinColor(int codePoint) {
        return codePoint >= 127995 && codePoint <= 127999;
    }

    // String str = new String(new int[]{0x1F3F4, 0xE0067, 0xE0062, 0xE0065, 0xE006E, 0xE0067, 0xE007F}, 0, 7);
    public static boolean isEmojiTagEnd(int codePoint) {
        return codePoint == 917631;
    }

    public static boolean isEmojiTagSpec(int codePoint) {
        return codePoint >= 917536 && codePoint <= 917630;
    }

    public static boolean isEmojiDecorateBlock(Character.UnicodeBlock block) {
        if (block == null) {
            return false;
        }
        return block.equals(Character.UnicodeBlock.VARIATION_SELECTORS)
                || block.equals(Character.UnicodeBlock.VARIATION_SELECTORS_SUPPLEMENT)
                || block.equals(Character.UnicodeBlock.COMBINING_HALF_MARKS)
                || block.equals(Character.UnicodeBlock.COMBINING_MARKS_FOR_SYMBOLS)
                || block.equals(Character.UnicodeBlock.COMBINING_DIACRITICAL_MARKS)
                || block.equals(Character.UnicodeBlock.COMBINING_DIACRITICAL_MARKS_SUPPLEMENT);
    }

    public static void pickAllEmoji(CharSequence data, StringBuilder removeResult, List<String> emojiList) {
        if (removeResult == null && emojiList == null) {
            return;
        }
        if (removeResult != null) {
            removeResult.delete(0, removeResult.length());
        }
        if (emojiList != null) {
            emojiList.clear();
        }
        if (data == null || data.length() == 0) {
            return;
        }
        StringBuilder emojiBuilder = new StringBuilder();
        int i = 0;
        int j;
        Character.UnicodeBlock block;
        while (i < data.length()) {
            if (i + 1 < data.length()) {
                block = Character.UnicodeBlock.of(data.charAt(i + 1));
                if (isEmojiDecorateBlock(block) || Character.UnicodeBlock.LOW_SURROGATES.equals(block)) {
                    if (i + 2 >= data.length()) {
                        emojiBuilder.append(data, i, i + 2);
                        break;
                    }
                    j = handleNationalFlag(data, i, emojiBuilder, emojiList);
                    if (i != j) {
                        i = j;
                        continue;
                    }
                    j = handleHumanSkin(data, i, emojiBuilder, emojiList);
                    if (i != j) {
                        i = j;
                        continue;
                    }
                    j = handleTagSequence(data, i, emojiBuilder, emojiList);
                    if (i != j) {
                        i = j;
                        continue;
                    }
                    emojiBuilder.append(data, i, i + 2);
                    i = handleNextChar(data, i + 2, emojiBuilder, emojiList);
                    continue;
                }
            }
            recordEmoji(emojiBuilder, emojiList);
            int type = Character.getType(data.charAt(i));
            if (type == (int) Character.OTHER_SYMBOL) {//特殊符號一律按照Emoji處理
                if (emojiList != null) {
                    emojiList.add(String.valueOf(data.charAt(i)));
                }
            } else if (removeResult != null) {
                removeResult.append(data.charAt(i));
            }
            i++;
        }
        recordEmoji(emojiBuilder, emojiList);
    }

    private static int handleNextChar(CharSequence data, int i, StringBuilder emojiBuilder, List<String> emojiList) {
        if (i >= data.length()) {
            return i;
        }
        char nextChar = data.charAt(i);
        if (nextChar == '\u200D') {//零寬度連接符
            emojiBuilder.append(nextChar);
            return i + 1;
        }
        int j = i;
        Character.UnicodeBlock block;
        while (j < data.length()) {
            nextChar = data.charAt(j);
            block = Character.UnicodeBlock.of(nextChar);
            if (isEmojiDecorateBlock(block)) {
                emojiBuilder.append(nextChar);
                j++;
            } else {
                break;
            }
        }
        if (i != j) {
            recordEmoji(emojiBuilder, emojiList);
        }
        return j;
    }

    private static int handleNationalFlag(CharSequence data, int i, StringBuilder emojiBuilder, List<String> emojiList) {
        int codePoint = Character.codePointAt(data, i);
        if (isEmojiNationalFlag(codePoint)) {//處理國旗類型
            recordEmoji(emojiBuilder, emojiList);//提交未處理
            if (i + 3 < data.length()) {
                codePoint = Character.codePointAt(data, i + 2);
                if (isEmojiNationalFlag(codePoint)) {
                    emojiBuilder.append(data, i, i + 4);
                    recordEmoji(emojiBuilder, emojiList);
                    i = i + 4;
                }
            }
            i = i + 2;
        }
        return i;
    }

    private static int handleHumanSkin(CharSequence data, int i, StringBuilder emojiBuilder, List<String> emojiList) {
        if (i + 3 >= data.length()) {
            return i;
        }
        int codePoint = Character.codePointAt(data, i + 2);
        if (isEmojiSkinColor(codePoint)) {//膚色修飾
            emojiBuilder.append(data, i, i + 4);
            recordEmoji(emojiBuilder, emojiList);
            i = i + 4;
        }
        return i;
    }

    private static int handleTagSequence(CharSequence data, int i, StringBuilder emojiBuilder, List<String> emojiList) {
        if (i + 3 >= data.length()) {
            return i;
        }
        int codePoint = Character.codePointAt(data, i + 2);
        if (isEmojiTagSpec(codePoint)) {
            emojiBuilder.append(data, i, i + 4);
            i = i + 4;
            while (i < data.length()) {
                codePoint = Character.codePointAt(data, i);
                if (isEmojiTagSpec(codePoint)) {
                    emojiBuilder.append(data, i, i + 2);
                    i = i + 2;
                } else if (isEmojiTagEnd(codePoint)) {
                    emojiBuilder.append(data, i, i + 2);
                    recordEmoji(emojiBuilder, emojiList);
                    i = i + 2;
                    break;
                } else { //error
                    break;
                }
            }
            emojiBuilder.delete(0, emojiBuilder.length());
        } else if (isEmojiTagEnd(codePoint)) {
            emojiBuilder.append(data, i, i + 4);
            recordEmoji(emojiBuilder, emojiList);
            i = i + 4;
        }
        return i;
    }

    private static void recordEmoji(StringBuilder builder, List<String> emojiList) {
        if (builder != null && builder.length() > 0) {
            if (emojiList != null) {
                emojiList.add(builder.toString());
            }
            builder.delete(0, builder.length());
        }
    }

}

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