复习笔记

<?php
$dh=opendir("./");
var_dump($dh);
$list=array();
while(($item=readdir($dh))!==false){
    $list[]=$item;

}
foreach ($list as $key => $value) {
    echo $value,'<br/>';
}
var_dump(readdir($dh));

$age=12;
class Human{
    public $name;
    public $age=19;
    public function __construct($name){
        $this->name=$name;
    }
    public static function eat(){
        echo '吃饭','<br/>';
    }
    public static function ha(){
        eat();
    }
    public function __destruct(){
        echo '对象销毁时自动调用';
    }
}
function eat(){
    echo "还吃",'<br/>';
}
eat();
Human::eat();
Human::ha();

$lisi=new Human('lisi');

//封装MySQL类
class MysqlFun{
    private $host;
    private $user;
    private $password;
    private $conn;
    public function __construct($host,$user,$password){
        $this->host=$host;
        $this->user=$user;
        $this->password=$password;
        $this->conn=mysql_connect('localhost','root','111111');
    }
    public function getConn(){
        // $conn=mysql_connect($this->host,$this->user,$this->password);
        return $this->conn;
    }
    //向数据库发送数据
    public function query($sql){
        return mysql_query($sql,$this->conn);
    }
    //查询多行数据，返回二维数组，一行数据一个一维数组
    public function getAll($sql){
        $rs=mysql_query($sql,$this->conn);
        $arr=array();
        while(($row=mysql_fetch_assoc($rs))!==false){
            $arr[]=$row;
        }
        return $arr;
    } 
    //查询一行数据，返回一维数组
    public function getRow($sql){
        $rs=mysql_query($sql,$this->conn);
        return mysql_fetch_assoc($rs);
    }
    //查询一行一列数据，返回那个值
    public function getOne($sql){
        $rs=mysql_query($sql.$this->conn);
        $arr=mysql_fetch_row($rs);
        return $arr[0];
    }
    public function close(){
        mysql_close($this->conn);
    }
}

$wode=new MysqlFun('localhost','root','111111');
$wode->query('set names utf8');
$wode->query('use test1');
$sql='select * from stu';
$array=$wode->getAll($sql);
print_r($array);

//继承extends
/*父类私有的属性，可以理解为不能继承，因为继承了但不能访问
protected修饰的属性，继承之后再子类内部能访问，但在类外部不能访问
*/
class animal{
    public function eat(){
        echo 'animal会吃';
    }
    protected function getmoney(){
        echo '我有好多钱';
    }
}
class people extends animal{
    public function __construct(){
        parent::eat();
    }
    public static function run(){
        echo '跑啊跑';
    }
}
$zhangsan=new people();
$zhangsan->run();
//静态方法也可以用对象名调用
class hum extends people{
    public function __construct(){
        $this->getmoney();
    }
}
$hu=new hum();
echo '<br/>';

?>

有些数据没有经过严格的验证，然后直接拼接 SQL 去查询。导致漏洞产生，比如：

$id  = $_GET['id'];
$sql = "SELECT name FROM users WHERE id = $id";

 因为没有对 $_GET['id'] 做数据类型验证，注入者可提交任何类型的数据，比如 " and 1= 1 or " 等不安全的数据。如果按照下面方式写，就安全一些。

$id  = intval($_GET['id']);
$sql = "SELECT name FROM users WHERE id = $id";

 复习笔记：