PHP object-oriented guide (17) Automatically loading classes_PHP tutorial

Automatically load classes
When many developers write object-oriented applications, they create a PHP source file for each class definition. A big
annoyance is having to write a long list of include files at the beginning of each script (one file per class).
In a software development system, it is impossible to write all classes in a PHP file. When a PHP file
needs to call a class declared in another file, it needs to include this File import. But sometimes,
In projects with many files, it is a headache to include all the files of the required classes one by one, so
Can we use any classes? When, then import the PHP file where this class is located? This is the autoloading class we
are going to talk about here.
In PHP5, you can define an __autoload() function, which will be automatically called when trying to use a class that has not yet been defined. By calling this function, the script engine has the last one before PHP fails with an error. Opportunity to load the required class. One parameter received by the
__autoload() function is the class name of the class you want to load. So when you are working on a project, you need to follow certain rules when organizing and defining the file name of the
class. According to the rules, it is best to center on the class name. You can also add a unified prefix or suffix to form a file name, such as xxx_classname.php, classname_xxx.php and classname.php, etc.
This example attempts to load the MyClass1 and MyClass2 classes from the MyClass1.php and MyClass2.php files respectively
Code snippets

Copy the code The code is as follows:

function __autoload($classname) {
require_once $classname . '.php';
}
//MyClass1 class does not exist for automatic calling __autoload() function, pass in the parameter "MyClass1"
$obj = new MyClass1();
//MyClass2 class does not exist, automatically call the __autoload() function, pass in the parameter "MyClass2"
$ obj2 = new MyClass2();
?>

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www.bkjia.comtruehttp: //www.bkjia.com/PHPjc/320614.htmlTechArticleAutomatically load classes. When many developers write object-oriented applications, they create a PHP source for each class definition. document. A big annoyance is having to do this in every script (one per class...