java 正则表达式检查代码是否包含非 UTF-8 字符？
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Regexp to check if code contains non-UTF-8 characters?
提问by user1340582
I am using PMD, checkstyle, findbugs, etc. in Sonar. I would like to have a rule verifying that Java code contains no characters not part of UTF-8.
我在声纳中使用 PMD、checkstyle、findbugs 等。我想要一个规则来验证 Java 代码不包含不属于 UTF-8 的字符。
E.g. the character ? should not be allowed
例如字符？不应该被允许
I could not find a rule for this in the above plugins, but I guess a custom rule can be made in Sonar.
我在上述插件中找不到相关规则，但我想可以在 Sonar 中制定自定义规则。
回答by kshepherd
Here is the regular expression which will match only valid UTF-8 byte sequences:
这是仅匹配有效 UTF-8 字节序列的正则表达式：
/^([\x00-\x7F]|[\xC2-\xDF][\x80-\xBF]|\xE0[\xA0-\xBF][\x80-\xBF]|[\xE1-\xEC][\x80-\xBF]{2}|\xED[\x80-\x9F][\x80-\xBF]|[\xEE-\xEF][\x80-\xBF]{2}|\xF0[\x90-\xBF][\x80-\xBF]{2}|[\xF1-\xF3][\x80-\xBF]{3}|\xF4[\x80-\x8F][\x80-\xBF]{2})*$/
I have derived it from RFC 3629 UTF-8, a transformation format of ISO 10646section 4 - Syntax of UTF-8 Byte Sequences.
我是从RFC 3629 UTF-8 中衍生出来的，它是 ISO 10646第 4 节的转换格式- UTF-8 字节序列的语法。
Factorizing the above gives the slightly shorter:
将上述因式分解得到略短的：
/^([\x00-\x7F]|([\xC2-\xDF]|\xE0[\xA0-\xBF]|\xED[\x80-\x9F]|(|[\xE1-\xEC]|[\xEE-\xEF]|\xF0[\x90-\xBF]|\xF4[\x80-\x8F]|[\xF1-\xF3][\x80-\xBF])[\x80-\xBF])[\x80-\xBF])*$/
This simple perl script demonstrates usage:
这个简单的 perl 脚本演示了用法：
#!/usr/bin/perl -w
my $passstring = "This string \xEF\xBF\xBD == ? is valid UTF-8";
my $failstring = "This string \x{FFFD} == ? is not valid UTF-8";
if ($passstring =~ /^([\x00-\x7F]|[\xC2-\xDF][\x80-\xBF]|\xE0[\xA0-\xBF][\x80-\xBF]|[\xE1-\xEC][\x80-\xBF]{2}|\xED[\x80-\x9F][\x80-\xBF]|[\xEE-\xEF][\x80-\xBF]{2}|\xF0[\x90-\xBF][\x80-\xBF]{2}|[\xF1-\xF3][\x80-\xBF]{3}|\xF4[\x80-\x8F][\x80-\xBF]{2})*$/)
{
print 'Passstring passed'."\n";
}
else
{
print 'Passstring did not pass'."\n";
}
if ($failstring =~ /^([\x00-\x7F]|[\xC2-\xDF][\x80-\xBF]|\xE0[\xA0-\xBF][\x80-\xBF]|[\xE1-\xEC][\x80-\xBF]{2}|\xED[\x80-\x9F][\x80-\xBF]|[\xEE-\xEF][\x80-\xBF]{2}|\xF0[\x90-\xBF][\x80-\xBF]{2}|[\xF1-\xF3][\x80-\xBF]{3}|\xF4[\x80-\x8F][\x80-\xBF]{2})*$/)
{
print 'Failstring passed'."\n";
}
else
{
print 'Failstring did not pass'."\n";
}
exit;
It produces the following output:
它产生以下输出：
Passstring passed
Failstring did not pass
