登录判断

//后台控制器方法
 public function h_login()
    {
    //登陆页面
    	if (IS_POST) {
    	    $data = I('post.');
            $verify =new \Think\Verify();//验证码错误
            $check = $verify->check($data['verify']);
            if (empty($data['username']) || empty($data['password'])) {
                $this->error('用户名或密码不能为空');
            }
            if (!$check) {
                $this->error('验证码错误');
            }
            $model = D('User');
            $res =$model->where(array("username" => $data['username']))->find();
            if ($res && $res['password'] == encrypt_password($data['password'])) {
               //encrypt_password 加密函数
                session('user_info',$res); //设置登录标识
                $this->success('登陆成功',U('Home/Center/center'));
            }else{
                $this->error('用户名或密码不正确');
            }       			
    	}else{
    		$this->display();
    	}  	
    } 

//加密函数放到Common/function
    function encrypt_password($password)
{
    $salt = 'dfskngflmgkosmfdofdlgf';//盐 加盐
    $key = substr($salt, 3, 8);
    return md5(md5($password) . $key);
}