php自动加载autoload机制示例分享

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
)

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