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php中自定义类文件自动加载

Jun 23, 2016 pm 01:09 PM

在php中,我们常常会引用很多类文件,如何实现多文件目录中,加载不同的文件呢?

php提供了几种自动加载函数

假定类文件是当前目录下的lib/User.class.php

1,自动加载函数:__autoload()

function __autoload($class){include 'lib/'.$class.'.class.php';}$User=new User();
Copy after login

解释:当实例化一个对象时,会在本页面查找有没有匹配的类,如果没有,会自动执行__autoload()方法,同时会把类的名称传给__autoload()这个方法,这样就可以引入与之匹配的类文件了(前提是类文件存在这个目录中)

2,自定义函数来加载类文件

通过函数spl_autoload_register()来实现

function A($class){include 'lib/'.$class.'.class.php';}spl_autoload_register('A');$User= new User();
Copy after login

解释:与上一个相同,也是先查找当前文件有没有匹配的类,然后再去执行自定义加载的函数,不同的是,如果与__autoload()同时存在的话,__autoload()不会被执行

3,自定义对象加载类文件

也是通过spl_autoload_register(array('对象','方法名称'))来实现

class A{    public function Aauto($class){    include 'lib/'.$class.'.class.php';    }}$A=new A();sql_autoload_register(array($A,'Aauto'));$User= new User();
Copy after login

与自定义函数来加载类文件是一样的,需要注意的是,顺序不要搞错了

4,指定静态方法加载类文件

spl_autoload_register(array('类名','静态方法名称'))来实现(两种写法)

第一种:

class A{    public function Aauto($class){    include 'lib/'.$class.'.class.php';    }}sql_autoload_register(array('A','Aauto'));$User= new User();
Copy after login

第二种:

class A{    public function Aauto($class){    include 'lib/'.$class.'.class.php';    }}sql_autoload_register(array('A::Aauto'));$User= new User();
Copy after login


以上方法都是个人总结,如有错误,希望告知,本人及时修改,谢谢!











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