PHP识别中文编码并自动转换为UTF-8

php中常用的字符转换函数iconv 和 mb_convert_encoding

1、iconv使用方法：

iconv("原编码", "目标编码//translit", 需要处理的字符串);

utf8转换为gbk
<?php
header("content-type:text/html;charset=utf-8");
echo $str= '你好,这里是utf8转gbk!';
echo '<br />';
echo iconv("utf-8","gbk//translit",$str); //将字符串的编码从utf-8转到gb2312

gbk转换为utf8
<?php
header("content-type:text/html;charset=gb2312");
echo $str= '你好,这里是gbk转utf8!';
echo '<br />';

 //将字符串的编码从gb2312转到utf-8
echo iconv('gb2312', 'utf-8', $str);

2、mb_convert_encoding

mb_convert_encoding(需要处理的字符串,  目标编码,  原编码);

3、识别中文编码并自动转换为utf-8

function charset($data) {
    if(!empty($data)) {
        $filetype = mb_detect_encoding($data, array('utf-8','gbk','latin1','big5'));
        if($filetype != 'utf-8') {
            $data = mb_convert_encoding($data ,'utf-8', $filetype);
        }
    }
    return $data;
}