c 中中文乱码_Java实现过滤中文乱码

矫情吗；* 2023-01-01 09:56 141阅读 0赞

**最近在日志数据清洗时遇到中文乱码，如果只要有非中文字符就将该字符串过滤掉，这种方法虽简单但并不可取，因为比如像Xperia™主題、天天四川麻将Ⅱ这样的字符串也会被过滤掉。**

**1. Unicode编码**

Unicode编码是一种涵盖了世界上所有语言、标点等字符的编码方式，简单一点说，就是一种通用的世界码；其编码范围：U+0000 .. U+10FFFF。按Unicode硬编码的区间进行划分，Unicode编码被分成若干个block ( Unicode block)；每一个Unicode编码专属于唯一的Unicode block，Unicode block之间互不重叠。从码字的本身的属性出发，Unicode编码被分成了若干script ( Unicode script)；比如，与中文相关的字符、标点的scriptHan包括block如下：

*  CJK Radicals Supplement
 *  Kangxi Radicals
 *  CJK Symbols and Punctuation中的15个字符
 *  CJK Unified Ideographs Extension A
 *  CJK Unified Ideographs
 *  CJK Compatibility Ideographs
 *  CJK Unified Ideographs Extension B
 *  CJK Unified Ideographs Extension C
 *  CJK Unified Ideographs Extension D
 *  CJK Unified Ideographs Extension E
 *  CJK Compatibility Ideographs Supplement

其中，常见的中文字符在CJK Unified Ideographs block；此外，考虑繁体字及不常见字等，CJK还有A、B、C、D、E五个extension。Basic Latin block完整地包含了ASCII码的控制字符、标点字符与英文字母字符。

**2. Java的字符编码**

JDK完整实现Unicode的block与script：

Char c = '☎'Character.UnicodeBlock ub = Character.UnicodeBlock.of(c)Character.UnicodeScript uc = Character.UnicodeScript.of(c);

`` `Java中的字符char内置的编码方式是UTF-16，当char强转成int类型时，其返回值是unicode编码值，只有当getbyte时才返回的是utf-8编码的byte：` `` ``

String s = "\u00a0";

`` `String.format("\\u%04x", (int) s.charAt(0)) // --> \u00a0` `import org.apache.commons.codec.binary.Hex;` `Hex.encodeHex(s.getBytes()) // --> c2a0`

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UTF-8是Unicode字符的变长前缀编码的一种实现，二者之间的对应关系在这里.现在我们回到开篇过滤中文乱码的问题，有一个基本解决思路：

去掉各种标点字符、控制字符，

计算剩下字符中非中文字符所占的比例，如果超过阈值，则认为该字符串为乱码串

完整代码如下：

public class ChineseUtill {
             private static boolean isChinese(char c) {
                 Character.UnicodeScript sc = Character.UnicodeScript.of(c);        if (sc == Character.UnicodeScript.HAN) {
                     return true;        }        return false;    }    public static boolean isPunctuation(char c) {
                 Character.UnicodeBlock ub = Character.UnicodeBlock.of(c);        if (    // punctuation, spacing, and formatting characters                ub == Character.UnicodeBlock.GENERAL_PUNCTUATION                // symbols and punctuation in the unified Chinese, Japanese and Korean script                || ub == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION                // fullwidth character or a halfwidth character                || ub == Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS                // vertical glyph variants for east Asian compatibility                || ub == Character.UnicodeBlock.CJK_COMPATIBILITY_FORMS                // vertical punctuation for compatibility characters with the Chinese Standard GB 18030                || ub == Character.UnicodeBlock.VERTICAL_FORMS                // ascii                || ub == Character.UnicodeBlock.BASIC_LATIN                ) {
                     return true;        } else {
                     return false;        }    }    private static Boolean isUserDefined(char c) {
                 Character.UnicodeBlock ub = Character.UnicodeBlock.of(c);        if (ub == Character.UnicodeBlock.NUMBER_FORMS                || ub == Character.UnicodeBlock.ENCLOSED_ALPHANUMERICS                || ub == Character.UnicodeBlock.LETTERLIKE_SYMBOLS                || c == '\ufeff'                || c == '\u00a0'                )            return true;        return false;    }    public static Boolean isMessy(String str)  {
                 float chlength = 0;        float count = 0;        for(int i = 0; i < str.length(); i++) {
                     char c = str.charAt(i);            if(isPunctuation(c) || isUserDefined(c))                continue;            else {
                         if(!isChinese(c)) {
                             count = count + 1;                }                chlength ++;            }        }        float result = count / chlength;        if(result > 0.3)            return true;        return false;    }}

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为了得到更为完整的可接受的字符表，定义isUserDefined方法(具体字符表与日志中的字符有关系)；加上了Number Forms、Enclosed Alphanumerics、Letterlike Symbols这三个block，以及\\u00a0(Non-breaking space)字符与\\ufeff(ZERO WIDTH NO-BREAK SPACE)字符。

作者：易霂  
链接：https://www.jianshu.com/p/5590b8ef0dec  
来源：简书  
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