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Specific application explanation of PHP5 magic function_PHP tutorial

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2016-07-15 13:29:17864browse

In PHP5 magic function 1, __construct() When an object is instantiated, this method of the object is first called. 

<ol class="dp-xml">
<li class="alt"><span><span>class Test   </span></span></li>
<li class=""><span>{   </span></li>
<li class="alt"><span> function __construct()   </span></li>
<li class=""><span> {   </span></li>
<li class="alt"><span>  echo "before";   </span></li>
<li class=""><span> }   </span></li>
<li class="alt">
<span>}   </span><span></span><span></span>
</li>
<li class="">
<span>$</span><span class="attribute"><font color="#ff0000">t</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">new</font></span><span> Test();  </span>
</li>
</ol>

The output is:

start

We know the php5 object model and The function with the same class name is the constructor of the class, so if we define the constructor and __construct() method at the same time, php5 will call the constructor by default and not the __construct() function, so __construct() is used as the class's constructor. Default constructor

PHP5 magic function 2, __destruct() This method is called when an object is deleted or the object operation terminates. 

<ol class="dp-xml">
<li class="alt"><span><span>class Test   </span></span></li>
<li class=""><span>{   </span></li>
<li class="alt"><span> function __destruct()   </span></li>
<li class=""><span> {   </span></li>
<li class="alt"><span>  echo "end";   </span></li>
<li class=""><span> }   </span></li>
<li class="alt"><span>}   </span></li>
<li class="">
<span>$</span><span class="attribute"><font color="#ff0000">t</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">new</font></span><span> Test(); </span>
</li>
</ol>

will output

end

We can perform operations such as releasing resources at the end of the object operation

PHP5 magic function 3, __get() When trying to read an attribute that does not exist time is called.

If you try to read a property that does not exist in an object, PHP will give an error message. If you add the __get method to the class, and we can use this function to implement various operations similar to reflection in java 

<ol class="dp-xml">
<li class="alt"><span><span>class Test   </span></span></li>
<li class=""><span>{   </span></li>
<li class="alt"><span> public function __get($key)   </span></li>
<li class=""><span> {   </span></li>
<li class="alt"><span>  echo $key . " 不存在";   </span></li>
<li class=""><span> }   </span></li>
<li class="alt"><span>}   </span></li>
<li class=""><span> </span></li>
<li class="alt"><span> </span></li>
<li class="">
<span>$</span><span class="attribute"><font color="#ff0000">t</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">new</font></span><span> Test();   </span>
</li>
<li class="alt">
<span>echo $t-</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>name;   </span>
</li>
<li class=""><span> </span></li>
<li class="alt"><span>就会输出：  </span></li>
<li class=""><span>name 不存在  </span></li>
</ol>

PHP5 magic function 4, __set() is called when trying to write a value to a property that does not exist. 

<ol class="dp-xml">
<li class="alt"><span><span>class Test   </span></span></li>
<li class=""><span>{   </span></li>
<li class="alt"><span> public function __set($key,$value)   </span></li>
<li class=""><span> {   </span></li>
<li class="alt"><span>  echo '对'.$key . "附值".$value;   </span></li>
<li class=""><span> }   </span></li>
<li class="alt"><span>}   </span></li>
<li class=""><span> </span></li>
<li class="alt"><span> </span></li>
<li class="">
<span>$</span><span class="attribute"><font color="#ff0000">t</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">new</font></span><span> Test();   </span>
</li>
<li class="alt">
<span>$t-</span><span class="tag"><strong><font color="#006699">></font></strong></span><span class="attribute"><font color="#ff0000">name</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">"aninggo"</font></span><span>;   </span>
</li>
<li class=""><span> </span></li>
<li class="alt"><span>就会输出：  </span></li>
<li class=""><span>对 name 附值 aninggo </span></li>
</ol>

PHP5 magic function 5, __call() When trying to call a method that does not exist on an object, call this method. 

<ol class="dp-xml">
<li class="alt"><span><span>class Test   </span></span></li>
<li class=""><span>{   </span></li>
<li class="alt"><span> public function __call($Key, $Args)   </span></li>
<li class=""><span> {   </span></li>
<li class="alt"><span>  echo "您要调用的 {$Key} 方法不存在。你传入的参数是：" . print_r($Args, true);   </span></li>
<li class=""><span> }   </span></li>
<li class="alt"><span>}   </span></li>
<li class=""><span> </span></li>
<li class="alt">
<span>$</span><span class="attribute"><font color="#ff0000">t</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">new</font></span><span> Test();   </span>
</li>
<li class="">
<span>$t-</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>getName(aning,go);  </span>
</li>
</ol>

The program will output:

The getName method you want to call does not exist. The parameters are: Array

(

[0] => aning

[1] => go

)

PHP5 magic function 6,__toString() when Called when printing an object

This method is similar to java's toString method. When we print the object directly, this function is called back 

<ol class="dp-xml">
<li class="alt"><span><span>class Test   </span></span></li>
<li class=""><span>{   </span></li>
<li class="alt"><span> public function __toString()   </span></li>
<li class=""><span> {   </span></li>
<li class="alt"><span>  return "打印 Test";   </span></li>
<li class=""><span> }   </span></li>
<li class="alt"><span>}   </span></li>
<li class=""><span> </span></li>
<li class="alt"><span> </span></li>
<li class="">
<span>$</span><span class="attribute"><font color="#ff0000">t</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">new</font></span><span> Test();   </span>
</li>
<li class="alt"><span> </span></li>
<li class=""><span>echo $t;   </span></li>
</ol>

run echo $t; When, $t->__toString(); will be called to output

Print Test

PHP5 Magic Function 7, __clone() When the object is cloned, it will be called 

<ol class="dp-xml">
<li class="alt"><span><span>class Test   </span></span></li>
<li class=""><span>{   </span></li>
<li class="alt"><span> </span></li>
<li class=""><span> public function __clone()   </span></li>
<li class="alt"><span> {   </span></li>
<li class=""><span>  echo "我被复制了！";   </span></li>
<li class="alt"><span> }   </span></li>
<li class=""><span>}  </span></li>
<li class="alt"><span> </span></li>
<li class="">
<span>$</span><span class="attribute"><font color="#ff0000">t</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">new</font></span><span> Test();   </span>
</li>
<li class="alt">
<span>$</span><span class="attribute"><font color="#ff0000">t1</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">clone</font></span><span> $t;  </span>
</li>
<li class=""><span> </span></li>
<li class="alt"><span>程序输出：  </span></li>
<li class=""><span>我被克隆了！ </span></li>
</ol>

PHP5 Magic Function 8. By the way, let me introduce several very COOl experimental functions provided in php5

(1) runkit_method_rename

This function can dynamically change the name of the function we call. 

<ol class="dp-xml">
<li class="alt"><span><span>class Test   </span></span></li>
<li class=""><span>{   </span></li>
<li class="alt"><span> </span></li>
<li class=""><span> function foo() {  </span></li>
<li class="alt"><span>        return "foo! ";  </span></li>
<li class=""><span>    }  </span></li>
<li class="alt"><span> </span></li>
<li class=""><span>}   </span></li>
<li class="alt"><span> </span></li>
<li class=""><span>runkit_method_rename(  </span></li>
<li class="alt"><span>    'Test', //类名  </span></li>
<li class=""><span>    'foo',//实际调用的函数  </span></li>
<li class="alt"><span>    'bar'//显示调用的函数  </span></li>
<li class=""><span>);  </span></li>
<li class="alt"><span> </span></li>
<li class=""><span>echo Test::bar();  </span></li>
<li class="alt"><span> </span></li>
<li class=""><span>程序将输出  </span></li>
<li class="alt"><span>　  </span></li>
<li class=""><span>foo!  </span></li>
</ol>

(2) runkit_method_add

This PHP5 magic function can dynamically add functions to a class

<ol class="dp-xml">
<li class="alt"><span><span>class Test   </span></span></li>
<li class=""><span>{   </span></li>
<li class="alt"><span> </span></li>
<li class=""><span> function foo() {  </span></li>
<li class="alt"><span>        return "foo! ";  </span></li>
<li class=""><span>    }  </span></li>
<li class="alt"><span> </span></li>
<li class=""><span>}   </span></li>
<li class="alt"><span> </span></li>
<li class=""><span>runkit_method_add(  </span></li>
<li class="alt"><span>    Test,  //类名  </span></li>
<li class=""><span>    'add', //新函数名  </span></li>
<li class="alt"><span>    '$num1, $num2',//传入参数  </span></li>
<li class=""><span>    'return $num1 + $num2;',//执行的代码  </span></li>
<li class="alt"><span>    RUNKIT_ACC_PUBLIC  </span></li>
<li class=""><span>);  </span></li>
<li class="alt"><span> </span></li>
<li class=""><span>// 调用   </span></li>
<li class="alt">
<span>echo $e-</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>add(12, 4); </span>
</li>
</ol>

(3)runkit_method_copy

You can copy the functions in class A to the class B and rename the PHP5 magic function 

<ol class="dp-xml">
<li class="alt"><span><span>class Foo {  </span></span></li>
<li class=""><span>    function example() {  </span></li>
<li class="alt"><span>        return "foo! ";  </span></li>
<li class=""><span>    }  </span></li>
<li class="alt"><span>}  </span></li>
<li class=""><span> </span></li>
<li class="alt"><span>class Bar {  </span></li>
<li class=""><span>    //空类  </span></li>
<li class="alt"><span>}  </span></li>
<li class=""><span> </span></li>
<li class="alt"><span>//执行拷贝  </span></li>
<li class=""><span>runkit_method_copy('Bar', 'baz', 'Foo', 'example');  </span></li>
<li class="alt"><span> </span></li>
<li class=""><span>//执行拷贝后的函数  </span></li>
<li class="alt"><span>echo Bar::baz();  </span></li>
</ol>

(4) runkit_method_redefine

Dynamicly modify the return value of the function

This PHP5 magic function allows us to easily implement MOCK testing of classes! Isn’t it cool?

  1. class Example {  
  2.     function foo() {  
  3.         return "foo! ";  
  4.     }  
  5. }  
  7. //创建一个测试对象  
  8. $e = new Example();  
  10. // 在测试对象之前输出  
  11. echo "Before: " . $e->foo();  
  13. // 修改返回值  
  14. runkit_method_redefine(  
  15.     'Example',  
  16.     'foo',  
  17.     '',  
  18.     'return "bar! ";',  
  19.     RUNKIT_ACC_PUBLIC  
  20. );  
  22. // 执行输出  
  23. echo "After: " . $e->foo();  

(5)runkit_method_remove

这个PHP5魔术函数就很简单了，看名字就能看出来了，动态的从类中移除函数

<ol class="dp-xml">
<li class="alt"><span><span>class Test {  </span></span></li>
<li class=""><span>    function foo() {  </span></li>
<li class="alt"><span>        return "foo! ";  </span></li>
<li class=""><span>    }  </span></li>
<li class="alt"><span>      </span></li>
<li class=""><span>    function bar() {  </span></li>
<li class="alt"><span>        return "bar! ";  </span></li>
<li class=""><span>    }  </span></li>
<li class="alt"><span>}  </span></li>
<li class=""><span> </span></li>
<li class="alt"><span>// 移除foo函数  </span></li>
<li class=""><span>runkit_method_remove(  </span></li>
<li class="alt"><span>    'Test',  </span></li>
<li class=""><span>    'foo'  </span></li>
<li class="alt"><span>);  </span></li>
<li class=""><span> </span></li>
<li class="alt"><span>echo implode(' ', get_class_methods('Test'));  </span></li>
<li class=""><span> </span></li>
<li class="alt"><span>程序输出  </span></li>
<li class=""><span>bar  </span></li>
</ol>

以上所介绍的代码就是关于PHP5魔术函数的具体应用方式。


www.bkjia.comtruehttp://www.bkjia.com/PHPjc/446384.htmlTechArticle在 PHP5魔术函数1，__construct() 当实例化一个对象的时候，这个对象的这个方法首先被调用。 classTest { function__construct() { echo"before"; } } $ t =...
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