validate/User.php

namespace app\home\validate;
use think\Validate;
use think\Db;
/**
 * 会员验证器
 */
class User extends Validate{
  protected $regex = [ 'username' => '[A-Za-z0-9_]+'];
  protected $rule = [
    'userAccount' => 'require|checkUserAccount:1|regex:username',
    'userPass' => 'require|min:5',
  ];
  protected $message = [
    'userAccount.require' => '账号不能为空',
    'userAccount.regex' => '用户名必须是数字、字母或下划线!',
    'userPass.require' => '密码不能为空',
    'userPass.min' => '密码不能少于5个字符',
  ];
  protected $scene = [
    'add' => ['userAccount','userPass'],
    'edit' => [], // 编辑的时候，不用验证账号，因为账号不能修改
  ];
  protected function checkUserAccount($value){       
    $where = [];
    $where['dataFlag'] = 1;
    $where['userAccount'] = $value;
    $rs = Db::name('user')->where($where)->count();
    return ($rs==0)?true:'账号已存在';
  }
}

public function ceshi(){
		$data['userAccount'] = 'zhangsan';
		$validate = new validate();
		if(!$validate->scene('add')->check($data)){
			dump($validate->getError());
			die;
		}
	}