Yii 规则怎么验证中文，英文，下划线，数字组成的昵称呢？ [ 2.0 版本 ]

https://www.yiichina.com/question/974

这里说的没明白

array('carmark','match','pattern'=>'/^[\u4e00-\u9fa5]{1}[a-zA-Z]{1}[a-zA-Z_0-9]{5}$/'),

我改成

['username','match','pattern'=>'/^[\x{4e00}-\x{9fa5}_A-Za-z0-9]+$/','message'=>'角色名由中文,字母,数字组成', 'on' => ['isname']],

难道不是这样吗。是我太天真了吗？
报错

name	"PHP Warning"
message	"preg_match(): Compilation failed: character value in \\x{} or \\o{} is too large at offset 9"