好几天没写博客了，其实有好多需要总结的，因为最近一直在忙着做项目，但是困惑了几天的smarty模板中截取包含中英文混合的字符串乱码的问题，终于解决了，所以记录下来，需要的朋友看一下：
出现乱码的原因：
对于字符串的截取，truncate函数只适合英文用户，对与中文用户来说，使用 truncate会出现乱码，而且对于中文英文混合串来说，截取同样个数的字符串，实际显示长度上却不同，一个中文的长度大致相当于两个英文的长度。此外，truncate不能同时兼容GB2312、UTF-8等编码。
解决方法：自己写一个扩展类使用
ThinkPHP使用的smarty的truncate变量调节器所在的类文件位置：ThinkPHP\Library\Vendor\Smarty\plugins，其中有一个就是modifier.truncate.php，我们不用这个，我们自己写一个来实现
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文件名：modifier.smartTruncate.php
<?<span>php
</span><span>/*</span><span>*
* 中英文多编码字符串截取
</span><span>*/</span><span>function</span> smartDetectUTF8(<span>$string</span><span>)
{
</span><span>static</span><span>$result</span> = <span>array</span><span>();
</span><span>if</span>(! <span>array_key_exists</span>(<span>$key</span> = <span>md5</span>(<span>$string</span>), <span>$result</span><span>))
{
</span><span>$utf8</span> = "<span> /^(?:
[\x09\x0A\x0D\x20-\x7E] # ASCII
| [\xC2-\xDF][\x80-\xBF] # non-overlong 2-byte
| \xE0[\xA0-\xBF][\x80-\xBF] # excluding overlongs
| [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2} # straight 3-byte
| \xED[\x80-\x9F][\x80-\xBF] # excluding surrogates
| \xF0[\x90-\xBF][\x80-\xBF]{2} # planes 1-3
| [\xF1-\xF3][\x80-\xBF]{3} # planes 4-15
| \xF4[\x80-\x8F][\x80-\xBF]{2} # plane 16
)+$/xs
</span>"<span>;
</span><span>$result</span>[<span>$key</span>] = <span>preg_match</span>(<span>trim</span>(<span>$utf8</span>), <span>$string</span><span>);
}
</span><span>return</span><span>$result</span>[<span>$key</span><span>];
}
</span><span>function</span> smartStrlen(<span>$string</span><span>)
{
</span><span>$result</span> = 0<span>;
</span><span>$number</span> = smartDetectUTF8(<span>$string</span>) ? 3 : 2<span>;
</span><span>for</span>(<span>$i</span> = 0; <span>$i</span> < <span>strlen</span>(<span>$string</span>); <span>$i</span> += <span>$bytes</span><span>)
{
</span><span>$bytes</span> = <span>ord</span>(<span>substr</span>(<span>$string</span>, <span>$i</span>, 1)) > 127 ? <span>$number</span> : 1<span>;
</span><span>$result</span> += <span>$bytes</span> > 1 ? 1.0 : 0.5<span>;
}
</span><span>return</span><span>$result</span><span>;
}
</span><span>function</span> smartSubstr(<span>$string</span>, <span>$start</span>, <span>$length</span> = <span>null</span><span>)
{
</span><span>$result</span> = ''<span>;
</span><span>$number</span> = smartDetectUTF8(<span>$string</span>) ? 3 : 2<span>;
</span><span>if</span>(<span>$start</span> < 0<span>)
{
</span><span>$start</span> = <span>max</span>(smartStrlen(<span>$string</span>) + <span>$start</span>, 0<span>);
}
</span><span>for</span>(<span>$i</span> = 0; <span>$i</span> < <span>strlen</span>(<span>$string</span>); <span>$i</span> += <span>$bytes</span><span>)
{
</span><span>if</span>(<span>$start</span> <= 0<span>)
{
</span><span>break</span><span>;
}
</span><span>$bytes</span> = <span>ord</span>(<span>substr</span>(<span>$string</span>, <span>$i</span>, 1)) > 127 ? <span>$number</span> : 1<span>;
</span><span>$start</span> -= <span>$bytes</span> > 1 ? 1.0 : 0.5<span>;
}
</span><span>if</span>(<span>is_null</span>(<span>$length</span><span>))
{
</span><span>$result</span> = <span>substr</span>(<span>$string</span>, <span>$i</span><span>);
}
</span><span>else</span><span> {
</span><span>for</span>(<span>$j</span> = <span>$i</span>; <span>$j</span> < <span>strlen</span>(<span>$string</span>); <span>$j</span> += <span>$bytes</span><span>)
{
</span><span>if</span>(<span>$length</span> <= 0<span>)
{
</span><span>break</span><span>;
}
</span><span>if</span>((<span>$bytes</span> = <span>ord</span>(<span>substr</span>(<span>$string</span>, <span>$j</span>, 1)) > 127 ? <span>$number</span> : 1) > 1<span>)
{
</span><span>if</span>(<span>$length</span> < 1.0<span>)
{
</span><span>break</span><span>;
}
</span><span>$result</span> .= <span>substr</span>(<span>$string</span>, <span>$j</span>, <span>$bytes</span><span>);
</span><span>$length</span> -= 1.0<span>;
}
</span><span>else</span><span> {
</span><span>$result</span> .= <span>substr</span>(<span>$string</span>, <span>$j</span>, 1<span>);
</span><span>$length</span> -= 0.5<span>;
}
}
}
</span><span>return</span><span>$result</span><span>;
}
</span><span>function</span> smarty_modifier_smartTruncate(<span>$string</span>, <span>$length</span> = 80, <span>$etc</span> = '...',<span>$break_words</span> = <span>false</span>, <span>$middle</span> = <span>false</span><span>)
{
</span><span>if</span> (<span>$length</span> == 0<span>)
</span><span>return</span> ''<span>;
</span><span>if</span> (smartStrlen(<span>$string</span>) > <span>$length</span><span>) {
</span><span>$length</span> -= smartStrlen(<span>$etc</span><span>);
</span><span>if</span> (!<span>$break_words</span> && !<span>$middle</span><span>) {
</span><span>$string</span> = <span>preg_replace</span>('/\s+?(\S+)?$/', '', smartSubstr(<span>$string</span>, 0, <span>$length</span>+1<span>));
}
</span><span>if</span>(!<span>$middle</span><span>) {
</span><span>return</span> smartSubstr(<span>$string</span>, 0, <span>$length</span>).<span>$etc</span><span>;
} </span><span>else</span><span> {
</span><span>return</span> smartSubstr(<span>$string</span>, 0, <span>$length</span>/2) . <span>$etc</span> . smartSubstr(<span>$string</span>, -<span>$length</span>/2<span>);
}
} </span><span>else</span><span> {
</span><span>return</span><span>$string</span><span>;
}
}
</span>?>注意：在判断字符长度时，一个中文字符算1.0，一个英文字符算0.5，截取子字符串时不会出现参差不齐的情况.
使用方法：
{<span>$content</span>|smartTruncate:5:"..."}ok,测试没有问题有问欢迎指出
以上就介绍了ThinkPHP+Smarty模板中截取包含中英文混合的字符串乱码的解决方案，包括了smarty模板,thinkphp方面的内容，希望对PHP教程有兴趣的朋友有所帮助。
