PHP基础之Autoload

PHP的自动加载autoload机制很重要，这里做2个小练习

原创文章，转载请注明：http://www.cnblogs.com/phpgcs

文件结构如下，2种方式实现自动加载

1，自定义函数

2，spl_autoload_register()

liuyuan@ebuinfo:/var/www/phpgcs/php_autoload$ ll ./*
-rw-rw-r-- 1 liuyuan liuyuan  800 Feb 19 11:39 ./func_autoload.php
-rw-rw-r-- 1 liuyuan liuyuan  906 Feb 19 11:28 ./spl_autoload.php

./include:
total 16
drwxrwxr-x 2 liuyuan liuyuan 4096 Feb 19 11:42 ./
drwxrwxr-x 3 liuyuan liuyuan 4096 Feb 19 11:43 ../
-rw-rw-r-- 1 liuyuan liuyuan  142 Feb 19 11:42 aClass.php
-rw-rw-r-- 1 liuyuan liuyuan  143 Feb 19 11:42 bClass.php

　　

首先看自定义函数方式：

<?php
    define('EOL', (PHP_SAPI == 'cli') ? PHP_EOL : '</ br>');
    print_r(get_included_files());
    echo EOL;
    print get_include_path();
    echo EOL;
    //set_include_path(get_include_path().PATH_SEPARATOR.'/var/www/ly_php/php_spl/include/');
    //set_include_path(dirname(__FILE__).'/include');
    //set_include_path(dirname(__FILE__).'/include/');

    function __autoload($className){
        $filename = './include/'.$className.'.php';
        //$filename = './include/'.$className.'.php';
        //$filename = '/var/www/ly_php/php_spl/include/'.$className.'.php';
        if(file_exists($filename)){
            include_once $filename;
        }else{
            exit('no file');
        }
    }

    $a = new aClass();
    $b = new bClass();
    print_r(get_included_files());
?>

　　运行结果如下：

liuyuan@ebuinfo:/var/www/phpgcs/php_autoload$ php func_autoload.php 
Array
(
    [0] => /var/www/phpgcs/php_autoload/func_autoload.php
)

.:/usr/share/php:/usr/share/pear
aClass is loaded
bClass is loaded
Array
(
    [0] => /var/www/phpgcs/php_autoload/func_autoload.php
    [1] => /var/www/phpgcs/php_autoload/include/aClass.php
    [2] => /var/www/phpgcs/php_autoload/include/bClass.php
)

　　

原创文章，转载请注明：http://www.cnblogs.com/phpgcs

第二种方式：

<?php
    class myLoader{
        public static function autoload($className){
            $filename = './include/'.$className.'.php';
            if(file_exists($filename)){
                include_once $filename;
            }else{
                exit('no file');
            }
        }
    }

    define('EOL', (PHP_SAPI == 'cli') ? PHP_EOL : '<br />');

    spl_autoload_register(array('myLoader', 'autoload'));

    /**
    *__autoload 方法在 spl_autoload_register 后会失效，因为 autoload_func 函数指针已指向 spl_autoload 方法
    * 可以通过下面的方法来把 _autoload 方法加入 autoload_functions list
    */
    //spl_autoload_register( '__autoload' );


    error_reporting(E_ALL^E_NOTICE^E_WARNING^E_ERROR);
    error_reporting(E_NOTICE | E_WARNING );

    $a = new aClass();
    print_r(get_included_files());
    echo EOL;
    $b = new bClass();
    echo EOL;
?>

　　

运行结果如下：

liuyuan@ebuinfo:/var/www/phpgcs/php_autoload$ php spl_autoload.php 
aClass is loaded
Array
(
    [0] => /var/www/phpgcs/php_autoload/spl_autoload.php
    [1] => /var/www/phpgcs/php_autoload/include/aClass.php
)

bClass is loaded

　　

扩展阅读：

http://www.ruanyifeng.com/blog/2008/07/php_spl_notes.html