__construct(), __destory(), __get(), __set(), __call(),_PHP tutorial in PHP

(1) __construct() is PHP's built-in constructor, which is automatically called by the PHP parsing engine. When an object is instantiated, this method of the object is first called.

Example: class Test

          {

              function __construct()

                {

echo "This is __construct function!";

             }

            function Test()

               {

echo "This is Test!";

           }

}

$objTest = new Test; // The result is "This is __construct function!"

(2) __destory() is PHP's built-in destructor. This method is called when an object is deleted or the object operation terminates, so operations such as releasing resources can be performed.

class Test

{

Function __destory()

          {

                echo "This is __destory function!";

}

}

$objTest = new Test; // The result is "This is __destory function!"

(3) __get() is called when trying to read a property that does not exist, similar to various reflection operations in Java.

class Test

{

Function __get($key)

{

echo $key, "doesn't exist!";

}

}

$objTest = new Test;

$objTest->Name; // The result is "Name does'nt exist!"

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

class Test

{

Function __set($key, $val)

          {

echo "Can't assign"" . $val . "" to ". $key;

}

}

$objTest = new Test;

$objTest->Name = "ljlwill"; // The result is "Can't assign "ljlwill" to Name"

(5) __call() This method is called when trying to call a method that does not exist on the object.

class Test

{

Function __call($key, $args)

{

echo "The function "". $key ."" doesn't exist. it's args are ". print_r($args);

}

}

$objTest = new Test;

$objTest->getName("2004", "ljlwill");

// The result is The function "getName" doesn't exist. it's args are: Array(

[0] => 2004;

[1] => ljlwill;

)

(6) __toString() is called when printing an object, similar to Java's toString method. This function is called back when we print the object directly.

class Test

{

Function __toString()

{

                return "This is Test!";

}

}

$objTest = new Test;

eho $objTest; // The result is "This is Test!"

(7) __clone() is called when the object is cloned.

class Test

{

         function __clone()

             {

echo "I am cloned!" ;
         }

}

$objTest = new Test;

$objCloneTest = clone $objTest; // The result is "I am cloned!"

http://www.bkjia.com/PHPjc/478729.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/478729.htmlTechArticle (1) __construct() is PHP’s built-in constructor, which is automatically called by the PHP parsing engine. When an instance When an object is transformed, this method of the object is first called. Example: c...