dingsongtao大哥，刚才那问题 续

[woshimajia0005]

http://topic.csdn.net/u/20100701/11/743c2632-aa16-4151-868e-30be67c9cc3e.html

我用你刚才的代码（如下），能正确转换中文到这种编码。：

<?php

$str = '上海';
$ss = new StrFormat_Ascii();
echo $ss->encode($str);

class StrFormat_Ascii{
    static function encode($var){
        $ascii = '';
        $strlen_var = strlen($var);
        for ($c = 0; $c < $strlen_var; ++$c) {

            $ord_var_c = ord($var{$c});

            switch (true) {
                case $ord_var_c == 0x08:
                    $ascii .= '\b';
                    break;
                case $ord_var_c == 0x09:
                    $ascii .= '\t';
                    break;
                case $ord_var_c == 0x0A:
                    $ascii .= '\n';
                    break;
                case $ord_var_c == 0x0C:
                    $ascii .= '\f';
                    break;
                case $ord_var_c == 0x0D:
                    $ascii .= '\r';
                    break;

                case $ord_var_c == 0x22:
                case $ord_var_c == 0x2F:
                case $ord_var_c == 0x5C:
                    $ascii .= '\\'.$var{$c};
                    break;

                case (($ord_var_c >= 0x20) && ($ord_var_c <= 0x7F)):
                    $ascii .= $var{$c};
                    break;

                case (($ord_var_c & 0xE0) == 0xC0):
                    $char = pack('C*', $ord_var_c, ord($var{$c + 1}));
                    $c += 1;
                    $utf16 = self::utf82utf16($char);
                    $ascii .= sprintf('\u%04s', bin2hex($utf16));
                    break;

                case (($ord_var_c & 0xF0) == 0xE0):
                    $char = pack('C*', $ord_var_c,
                                 ord($var{$c + 1}),
                                 ord($var{$c + 2}));
                    $c += 2;
                    $utf16 = self::utf82utf16($char);
                    $ascii .= sprintf('\u%04s', bin2hex($utf16));
                    break;

                case (($ord_var_c & 0xF8) == 0xF0):
                    $char = pack('C*', $ord_var_c,
                                 ord($var{$c + 1}),
                                 ord($var{$c + 2}),
                                 ord($var{$c + 3}));
                    $c += 3;
                    $utf16 = self::utf82utf16($char);
                    $ascii .= sprintf('\u%04s', bin2hex($utf16));
                    break;

                case (($ord_var_c & 0xFC) == 0xF8):
                    $char = pack('C*', $ord_var_c,
                                 ord($var{$c + 1}),
                                 ord($var{$c + 2}),
                                 ord($var{$c + 3}),
                                 ord($var{$c + 4}));
                    $c += 4;
                    $utf16 = self::utf82utf16($char);
                    $ascii .= sprintf('\u%04s', bin2hex($utf16));
                    break;

                case (($ord_var_c & 0xFE) == 0xFC):
                    $char = pack('C*', $ord_var_c,
                                 ord($var{$c + 1}),
                                 ord($var{$c + 2}),
                                 ord($var{$c + 3}),
                                 ord($var{$c + 4}),
                                 ord($var{$c + 5}));
                    $c += 5;
                    $utf16 = self::utf82utf16($char);
                    $ascii .= sprintf('\u%04s', bin2hex($utf16));
                    break;
            }
        }

        return $ascii;
    }
    
    static function decode($var){
        $chrs = $var;
        $utf8 = '';
        $strlen_chrs = strlen($chrs);

        for ($c = 0; $c < $strlen_chrs; $c++) {

            $substr_chrs_c_2 = substr($chrs, $c, 2);
            $ord_chrs_c = ord($chrs{$c});

            switch (true) {
                case $substr_chrs_c_2 == '\b':
                    $utf8 .= chr(0x08);
                    ++$c;
                    break;
                case $substr_chrs_c_2 == '\t':
                    $utf8 .= chr(0x09);
                    ++$c;
                    break;
                case $substr_chrs_c_2 == '\n':
                    $utf8 .= chr(0x0A);
                    ++$c;
                    break;
                case $substr_chrs_c_2 == '\f':
                    $utf8 .= chr(0x0C);
                    ++$c;
                    break;
                case $substr_chrs_c_2 == '\r':
                    $utf8 .= chr(0x0D);
                    ++$c;
                    break;

                case $substr_chrs_c_2 == '\\"':
                case $substr_chrs_c_2 == '\\\'':
                case $substr_chrs_c_2 == '\\\\':
                case $substr_chrs_c_2 == '\\/':
                    if (($delim == '"' && $substr_chrs_c_2 != '\\\'') ||
                       ($delim == "'" && $substr_chrs_c_2 != '\\"')) {
                        $utf8 .= $chrs{++$c};
                    }
                    break;

                case preg_match('/\\\u[0-9A-F]{4}/i', substr($chrs, $c, 6)):
                    $utf16 = chr(hexdec(substr($chrs, ($c + 2), 2)))
                           . chr(hexdec(substr($chrs, ($c + 4), 2)));
                    $utf8 .= self::utf162utf8($utf16);
                    $c += 5;
                    break;

                case ($ord_chrs_c >= 0x20) && ($ord_chrs_c <= 0x7F):
                    $utf8 .= $chrs{$c};
                    break;

                case ($ord_chrs_c & 0xE0) == 0xC0:
                    $utf8 .= substr($chrs, $c, 2);
                    ++$c;
                    break;

                case ($ord_chrs_c & 0xF0) == 0xE0:
                    $utf8 .= substr($chrs, $c, 3);
                    $c += 2;
                    break;

                case ($ord_chrs_c & 0xF8) == 0xF0:
                    $utf8 .= substr($chrs, $c, 4);
                    $c += 3;
                    break;

                case ($ord_chrs_c & 0xFC) == 0xF8:
                    $utf8 .= substr($chrs, $c, 5);
                    $c += 4;
                    break;

                case ($ord_chrs_c & 0xFE) == 0xFC:
                    $utf8 .= substr($chrs, $c, 6);
                    $c += 5;
                    break;

            }

        }

        return $utf8;    
    }

    static function utf82utf16($utf8){
        if(function_exists('mb_convert_encoding')) {
            return mb_convert_encoding($utf8, 'UTF-16', 'UTF-8');
        }

        switch(strlen($utf8)) {
            case 1:
                return $utf8;

            case 2:
                return chr(0x07 & (ord($utf8{0}) >> 2))
                     . chr((0xC0 & (ord($utf8{0}) << 6))
                         | (0x3F & ord($utf8{1})));

            case 3:
                return chr((0xF0 & (ord($utf8{0}) << 4))
                         | (0x0F & (ord($utf8{1}) >> 2)))
                     . chr((0xC0 & (ord($utf8{1}) << 6))
                         | (0x7F & ord($utf8{2})));
        }
        return '';
    }
    
    static function utf162utf8($utf16){
        if(function_exists('mb_convert_encoding')) {
            return mb_convert_encoding($utf16, 'UTF-8', 'UTF-16');
        }
        $bytes = (ord($utf16{0}) << 8) | ord($utf16{1});
        switch(true) {
            case ((0x7F & $bytes) == $bytes):
                return chr(0x7F & $bytes);

            case (0x07FF & $bytes) == $bytes:
                return chr(0xC0 | (($bytes >> 6) & 0x1F))
                     . chr(0x80 | ($bytes & 0x3F));

            case (0xFFFF & $bytes) == $bytes:
                return chr(0xE0 | (($bytes >> 12) & 0x0F))
                     . chr(0x80 | (($bytes >> 6) & 0x3F))
                     . chr(0x80 | ($bytes & 0x3F));
        }
        return '';
    }
}
?>

被转换的中文字符串，直接在该程序文件中直接定义的（如上面的：

$str = '上海';
$ss = new StrFormat_Ascii();
echo $ss->encode($str);

（这样直接在程序中指定中文字符串内容时，能正确转换...）


但如果被转换的字符串是通过 GET 方式传递获取的，例如下：

$str = $_GET['str'];
$ss = new StrFormat_Ascii();
echo $ss->encode($str);

那么这样就好像就得到所需要的结果，要么是\u0000，要么是空的..... 我加上urldecode 也同样这问题...

[Dleno]

$str = '上海';
$ss = new StrFormat_Ascii();
echo $ss->encode($str);
//======================
//那个类只能是转换utf-8格式的，与老大的那个的差别也在前个帖子里说了。
//都是需要转换编码的。
//这里正确是因为你的PHP页面的文档编码本就是UTF-8的，所以不用转换，直接就可以。

$str = $_GET['str'];
$ss = new StrFormat_Ascii();
echo $ss->encode($str);
//=======================
//而这里不可以，应该是因为你前台页面的编码不是utf-8，所以$_GET['str'];得到的字符串也不是utf-8的，所以这里就需要用iconv转码了，
//如你页面编码是gb2312，则
$str = iconv("GB2312","UTF-8",$_GET['str']);
$ss = new StrFormat_Ascii();
echo $ss->encode($str);

[Dleno]

最好的就是你页面的编码也用utf-8格式的，就不用转了，不过改页面的编码也会涉及到数据库的编码，也就是要统一编码。
一般来说，建议都用utf-8的编码，一是它更通用，二是在PHP里有些内置函数的处理上，都会直接支持utf-8的编码，而不用做特殊处理，比如有的图片处理等函数，就不能直接用gb2312的字符，而需要转码为utf-8。
当然还有其他地方也会有这种情况。而又不会有错误出来，很难找出来问题所在。