PHP __construct (), __destory (), __get (), __set (), __call (), _php tutorial

(1) __construct () is a PHP built-in constructor that is automatically invoked with the PHP parsing engine, which is invoked first when an object is instantiated.

Example: Class Test

{

function __construct ()

{

echo "This is __construct function!";

}

function Test ()

{

echo "This is test!";

}

}

$objTest = new Test; The result of the operation was "this is __construct function!"

(2) __destory () is a built-in destructor for PHP, which is called when an object or object operation is dropped, so operations such as freeing resources can be done.

Class Test

{

function __destory ()

{

echo "This is __destory function!";

}

}

$objTest = new Test; The result of the operation was "this is __destory function!"

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

Class Test

{

function __get ($key)

{

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

}

}

$objTest = new Test;

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

(4) __set () is called when an attempt is made 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 run result is "Can ' t Assign" Ljlwill "to Name"

(5) __call () Call this method when attempting to invoke a method that does not exist for an 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 operation 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 the ToString method of Java, when we directly print the object callback with this function.

Class Test

{

function __tostring ()

{

Return "This is test!";

}

}

$objTest = new Test;

Eho $objTest; The result of the operation was "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; Operation result is "I am cloned!"

http://www.bkjia.com/PHPjc/478729.html www.bkjia.com true http://www.bkjia.com/PHPjc/478729.html techarticle (1) __construct () is a PHP built-in constructor that is automatically invoked with the PHP parsing engine, which is invoked first when an object is instantiated. Example: C ...

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