PHP 版本 > 5.2，json_encode 自带转义。如果是旧版本的 PHP 则可以用下面的函数
# list from www.json.org: (\b backspace, \f formfeed)
public function escapeJsonString($value) {
$escapers = array("\\", "/", "\"", "\n", "\r", "\t", "\x08", "\x0c");
$replacements = array("\\\\", "\\/", "\\\"", "\\n", "\\r", "\\t", "\\f", "\\b");
$result = str_replace($escapers, $replacements, $value);
return $result;
}
来自：http://www.nowamagic.net/librarys/veda/detail/2719
原文：http://my.oschina.net/u/576375/blog/400885