Automatic loading of classes_PHP tutorial

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PHP will report a fatal error when you try to use an undefined class. The solution is to add a class, which can be included in a file. After all, you know which class to use. However, PHP provides classes The autoloading function, which can save programming time. When you try to use a class that PHP has not organized, it will look for a global function __autoload. If this function exists, PHP will call it with a parameter, which is The name of the class.

Example 6.15 illustrates how __autoload is used. It assumes that each file in the current directory corresponds to a class. When the script attempts to generate an instance of class User, PHP will execute __autoload. The script assumes that the User class is defined in class_User.php .. Regardless of whether the call is in uppercase or lowercase, PHP will return the lowercase version of the name.

Listing 6.15 Class autoloading


//define autoload function
function __autoload($class)
{
include("class_" . ucfirst($class) . ".php");
}

//use a class that must be autoloaded
$u = new User;
$u->name = "Leon";
$u->printName();
?>

http://www.bkjia.com/PHPjc/445556.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/445556.htmlTechArticleWhen you try to use an undefined class, PHP will report a fatal error. The solution is to add a class , you can use include to include a file. You know which class to use. But...