php iconv() : Detected an illegal character in input string

作者:网络 来源:佚名 更新时间:2010-12-06 13:30:03 点击:

PHP传给JS字符串用ecsape转换加到url里,又用PHP接收,再用网上找的unscape函数转换一下,这样得到的字符串是UTF-8的,但我需要的是GB2312,于是用iconv转换,开始是这样用的
$str = iconv('UTF-8', 'GB2312', unescape(isset($_GET['str'])? $_GET['str']:''));
上线后报一堆这样的错:iconv() : Detected an illegal character in input string

考虑到GB2312字符集比较小,换个大的吧,于是改成GBK:
$str = iconv('UTF-8', 'GBK', unescape(isset($_GET['str'])? $_GET['str']:''));
上线后还是报同样的错!

再认真读手册,发现有这么一段:
If you append the string //TRANSLIT to out_charset transliteration is activated. This means that when a character can't be represented in the target charset, it can be approximated through one or several similarly looking characters. If you append the string //IGNORE, characters that cannot be represented in the target charset are silently discarded. Otherwise, str is cut from the first illegal character.
于是改成:
$str = iconv('UTF-8', 'GBK//IGNORE', unescape(isset($_GET['str'])? $_GET['str']:''));
本地测试//IGNORE能忽略掉它不认识的字接着往下转,并且不报错,而//TRANSLIT是截掉它不认识的字及其后面的内容,并且报错。//IGNORE是我需要的。
现在等待上线看结果(这样不是好的做法,继续琢磨手册,上网搜搜看),呵呵。。。

在网上找到下面这篇文章,发现mb_convert_encoding也可以,但效率比iconv差。


转换字符串编码iconv与mb_convert_encoding的区别

iconv — Convert string to requested character encoding(PHP 4 >= 4.0.5, PHP 5)
mb_convert_encoding — Convert character encoding(PHP 4 >= 4.0.6, PHP 5)

用法:
string mb_convert_encoding ( string str, string to_encoding [, mixed from_encoding] )
需要先启用 mbstring 扩展库,在 php.ini里将; extension=php_mbstring.dll 前面的 ; 去掉

string iconv ( string in_charset, string out_charset, string str )
注意:
第二个参数,除了可以指定要转化到的编码以外,还可以增加两个后缀://TRANSLIT 和 //IGNORE,
其中:
//TRANSLIT 会自动将不能直接转化的字符变成一个或多个近似的字符,
//IGNORE 会忽略掉不能转化的字符,而默认效果是从第一个非法字符截断。
Returns the converted string or FALSE on failure.

使用:
1. 发现iconv在转换字符"-"到gb2312时会出错,如果没有ignore参数,所有该字符后面的字符串都无法被保存。不管怎么样,这个"-"都无法转换成功,无法输出。另外mb_convert_encoding没有这个bug.
2. mb_convert_encoding 可以指定多种输入编码,它会根据内容自动识别,但是执行效率比iconv差太多;如:$str = mb_convert_encoding($str,"euc-jp","ASCII,JIS,EUC-JP,SJIS,UTF- 8");“ASCII,JIS,EUC-JP,SJIS,UTF-8”的顺序不同效果也有差异
3. 一般情况下用 iconv,只有当遇到无法确定原编码是何种编码,或者iconv转化后无法正常显示时才用mb_convert_encoding 函数

from_encoding is specified by character code name before conversion. it can be array or string - comma separated enumerated list. If it is not specified, the internal encoding will be used.

$str = mb_convert_encoding($str, "UCS-2LE", "JIS, eucjp-win, sjis-win");
$str = mb_convert_encoding($str, "EUC-JP', "auto");

例子:
$content = iconv("GBK", "UTF-8", $content);
$content = mb_convert_encoding($content, "UTF-8", "GBK");