Detailed introduction to object PHP serialization_PHP tutorial

We all know that PHP serialization can convert variables, including objects, into continuous bytes data. You can store the serialized variables in a file or transmit them over the network, and then deserialize them. Restore to original data. This article gives you a detailed introduction to PHP serialization. PHP can successfully store the properties and methods of a class that you define before deserializing its object. Sometimes you may need an object to be executed immediately after deserializing it. For such purposes, PHP automatically looks for the __sleep and __wakeup methods.

When an object is serialized by PHP, PHP will call the __sleep method (if it exists). After deserializing an object, PHP will Call the __wakeup method. Neither method accepts parameters. The __sleep method must return an array containing the properties that need to be serialized. PHP will discard the values ​​of other properties. Without the __sleep method, PHP will save all attributes. Example 1 shows how to use the __sleep and __wakeup methods to serialize an object. The Id attribute is a temporary attribute that is not intended to be retained in the object. The __sleep method guarantees that the id attribute is not included in the serialized object. When reversed To serialize a User object, the __wakeup method establishes a new value for the id attribute. This example is designed to be self-sustaining. In actual development, you may find that objects containing resources (such as images or data streams) require these methods.

<ol class="dp-xml">
<li class="alt"><span><span>Listing1 Object serialization  </span></span></li>
<li class=""><span>class User  </span></li>
<li class="alt"><span>{  </span></li>
<li class=""><span>public $name;  </span></li>
<li class="alt"><span>public $id;  </span></li>
<li class=""><span>function __construct()  </span></li>
<li class="alt"><span>{  </span></li>
<li class=""><span>//give user a unique ID 赋予一个不同的ID  </span></li>
<li class="alt">
<span>$this-＞</span><span class="attribute"><font color="#ff0000">id</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">uniqid</font></span><span>();  </span>
</li>
<li class=""><span>}  </span></li>
<li class="alt"><span>function __sleep()  </span></li>
<li class=""><span>{  </span></li>
<li class="alt"><span>//do not serialize this-＞id 不串行化id  </span></li>
<li class=""><span>return(array("name"));  </span></li>
<li class="alt"><span>}  </span></li>
<li class=""><span>function __wakeup()  </span></li>
<li class="alt"><span>{  </span></li>
<li class=""><span>//give user a unique ID  </span></li>
<li class="alt">
<span>$this-＞</span><span class="attribute"><font color="#ff0000">id</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">uniqid</font></span><span>();  </span>
</li>
<li class=""><span>}  </span></li>
<li class="alt"><span>}  </span></li>
<li class=""><span>//create object 建立一个对象  </span></li>
<li class="alt">
<span>$</span><span class="attribute"><font color="#ff0000">u</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">new</font></span><span> User;  </span>
</li>
<li class="">
<span>$u-＞</span><span class="attribute"><font color="#ff0000">name</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">"Leon"</font></span><span>;  </span>
</li>
<li class="alt"><span>//serialize it 串行化 注意不串行化id属性，id的值被抛弃  </span></li>
<li class="">
<span>$</span><span class="attribute"><font color="#ff0000">s</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">serialize</font></span><span>($u);  </span>
</li>
<li class="alt"><span>//unserialize it 反串行化 id被重新赋值  </span></li>
<li class="">
<span>$</span><span class="attribute"><font color="#ff0000">u2</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">unserialize</font></span><span>($s);  </span>
</li>
<li class="alt"><span>//$u and $u2 have different IDs $u和$u2有不同的ID  </span></li>
<li class=""><span>print_r($u);  </span></li>
<li class="alt"><span>print_r($u2);  </span></li>
<li class=""><span>?＞  </span></li>
</ol>

http://www.bkjia.com/PHPjc/446474.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/446474.htmlTechArticleWe all know that PHP serialization can convert variables, including objects, into continuous bytes data. You can convert strings The delineated variables are stored in a file or transmitted over the network, and then reflected...