Analysis of Implementation Method of Automatic Loading Mechanism of PHP Class

This paper describes the implementation method of automatic loading mechanism of PHP class with examples. Share it for your reference, as follows:

Test1.class.php

<?php
class Test1
{
  public static function test() {
    echo "hello,world!\n";
  }
}

Test2.class.php

<?php
class Test2
{
  public static function test() {
    echo " Hello, world !\n";
  }
}

test.php

<?php
Test1::test();

If you write directly, you will report an error

Fatal error: Class 'Test1' not found in /home/wwwroot/default/codelabs/test.php on line 3

Need to import files

<?php
require "Test1.class.php";
Test1::test();

So you can access it.

However, if there are more classes, more and more code will be introduced.

You need to use it at this time __autoload Method.

<?php
Test1::test();
function __autoload($class) {
  //require "Test1.class.php";
  //require "Test2.class.php";
  require __DIR__."/".$class.".class.php"; // __DIR__ Is the absolute path to the current directory 
}

When the program finds that no class is introduced, it will automatically call this method and introduce the class file.

Take one step to optimize and upgrade,

Multiple auto-loads are supported.

<?php
spl_autoload_register('__autoload1');
spl_autoload_register('__autoload2');
Test1::test();
Test2::test();
//  This method is automatically called when a classless load is detected 
function __autoload1($class) {
  //require "Test1.class.php";
  //require "Test2.class.php";
  require __DIR__."/".$class.".class.php"; // __DIR__ Is the absolute path to the current directory 
}
function __autoload2($class) {
  //require "Test1.class.php";
  //require "Test2.class.php";
  require __DIR__."/".$class.".class.php"; // __DIR__ Is the absolute path to the current directory 
}

Very good, very powerful!

For more readers interested in PHP related content, please check the topics on this site: "Introduction to php Object-Oriented Programming", "Encyclopedia of PHP Array (Array) Operation Skills", "Introduction to PHP Basic Syntax", "Summary of PHP Operation and Operator Usage", "Summary of php String (string) Usage", "Introduction to php+mysql Database Operation" and "Summary of php Common Database Operation Skills"

I hope this article is helpful to everyone's PHP programming.