PHP object-oriented - detailed code explanation of object serialization serialize(), __sleep(), __wakeup()

Sometimes it is necessary to upload an object to the network for transmission. In order to facilitate transmission, the entire object can be converted into a binary string, and then restored to the original when it reaches the other end. Object, this process is called serialization (also called serialization), just like we now want to transport a car to the United States by ship, because the car is relatively large, we can dismantle the car into smaller ones parts, and then we ship these parts to the United States by wheel, and then assemble these parts back into the car. Generally speaking, serialization is a method of converting the "memory" data represented by a
variable into a "string" data form and persisting it on the hard disk; while deserialization It's a reverse process. There are two situations where we must serialize objects. The first situation is to serialize an object when transmitting it over the network. The second situation is to write the object to a file or database. Serialization is sometimes used.
There are two processes in serialization. One is serialization, which is to convert the object into a binary string. We use the serialize() function to serialize an object, and the other is deserialization (also called Deserialization) is to convert the binary string converted from the object into an object. We use the unserialize() function to deserialize an object.
The parameter of the serialize() function in PHP is the object name, and the return value is a string. The string returned by Serialize() has ambiguous meaning. Generally, we will not parse this string to get the object information. We only need to return This string can be transmitted to the other end of the network or saved to a file.
The unserialize() function in PHP is used to deserialize objects. The parameter of this function is the return value of the serialize() function. The output is of course the reorganized object.
　

Serialization of objects:

1. Serializing an object can only "save" its attribute data, and the method is Ignore (method is not data)

2. When an object is serialized, the magic method of the class to which the object belongs is automatically called: sleep()

Deserialization of objects:

1. Deserializing an object is actually the attribute data originally saved during the recovery period, and you must rely on it at this time. The object's original class.

2. When an object is deserialized, the magic method of the class to which the object belongs is automatically called: wakeup()

All serialization

##1.serialize(object name) Serialize the specified class object $str=serialize($per) //Serialize the per object and return the result to $str

Serialization method:

<strong>$v1 = 123; //这是一个变量，代表任意的内存数据$s1 = serialize( $v1 );  //将任何类型的变量数据，转换为“字符串”
file_put_contents( &#39;要保存的目标文本文件&#39;, $s1 );    //将该字符串，保存到一个文件里（就是硬盘数据）</strong>

2.unserialize (return value after serialization) Deserialization, the return result is an object $per=unserialize($str);

Deserialization practice:

<strong>$s1 = file_get_contens( &#39;保存序列化数据的目标文本文件&#39; );    //从一个文件里读出其中的所有字符
$v1 = unserialize($s1);   //将该字符串数据，反序列化转换为变量（数据）</strong>

Examples of serialization and deserialization

<strong><?phpclass Person{
    var $name;
    var $sex;
    var $age;

    function construct($name = "", $sex = "", $age = "") {
        $this->name = $name;
        $this->sex = $sex;
        $this->age = $age;
    }    function say() {
        echo "我的名字叫：" . $this->name . " 性别：" . $this->sex . " 我的年龄是：" . $this->age . "<br>";
    }
}$p1 = new Person("张三", "男", 20);$p1_string = serialize($p1);    //把一个对象串行化，返一个字符串
echo $p1_string . "<br>";
//串行化的字符串我们通常不去解析//将$p1_string存储到文件file.txt中file_put_contents(&#39;./file.txt&#39;, $p1_string);
$p2 = unserialize($p1_string);    //把一个串行化的字符串反串行化形成对象
$p2$p2->say();//下面的做法和上面效果一样
$p3_file = file_get_contents(&#39;./file.txt&#39;); //读取文件
$p3 = unserialize($p3_file); //反序列化
$p3->say();?></strong>

Output results of the above example:

O:6:"Person":3:{s:4:"name";s:4:"张三";s:3:"sex";s:2:"男";s:3:"age";i:20;}我的名字叫：张三 性别：男 我的年龄是：20

Partial serialization

1.sleep() Serialize a certain Some properties of the object.

2.wakeup() When deserializing, initialize (actually modify) the object content

In PHP5 The two magic methods sleep() method and wakeup() method. When the object is serialized, a sleep() method will be called to complete some things before going to bed; and when it wakes up again, it will re-form a binary string. object, another PHP function wakeup() will be automatically called to do some actions that the object will do when it wakes up. The sleep() function does not accept any parameters, but returns an

array
containing the attributes that need to be serialized. Attributes that are not included will be ignored during serialization. If there is no sleep() method, PHP will save all attributes.

<a href="https://www.php.cn/wiki/58.html" target="_blank"><?class Person{

    var $name;
    var $sex;
    var $age;

    function construct($name = "", $sex = "", $age = "") {
        $this->name = $name;
        $this->sex = $sex;
        $this->age = $age;
    }    function say() {
        echo "我的名字叫：" . $this->name . " 性别：" . $this->sex . " 我的年龄是：" . $this->age . "<br>";
    }    //指定串行化时把返回的数组中$name和$age值串行化，忽略没在数组中的属性$sex
    function sleep() {
        $arr = array("name", "age"); // 此时，属性$sex将被删除！！！

        return($arr);
    }    //重新生成对象时，并重新赋值$age为40
    function wakeup() {
        $this->age = 40;
    }
}$p1 = new Person("张三", "男", 20);//把一个对象串行化，返一个字符串，调用了sleep()方法,忽略没在数组中的属性
$sex$p1_string = serialize($p1);
echo $p1_string . "<br>"; //串行化的字符串我们通常不去解析
$p2 = unserialize($p1_string); //反串行化形成对象$p2重新赋值
$age为40
$p2->say();?></a>

The output of the above example is:

O:6:"Person":2:{s:4:"name";s:4:"张三";s:3:"age";i:20;}我的名字叫：张三 性别： 我的年龄是：40

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