中文名称截取 php

// 中文名称截取;
function substr_cut($user_name){
    $strlen= mb_strlen($user_name, 'utf-8');
    $firstStr= mb_substr($user_name, 0, 1, 'utf-8');
    $lastStr= mb_substr($user_name, -1, 1, 'utf-8');
    return $strlen== 2 ? $firstStr . str_repeat('*', mb_strlen($user_name, 'utf-8') - 1) : $firstStr . str_repeat("*", $strlen - 2) . $lastStr;
}