如何在PHP中动态实例化一个对象？ [英] How to dynamically instantiate an object in PHP?

问题描述

我们可以在PHP中动态创建和初始化一个对象吗？
这是正常的代码：

  class MyClass {
 var $ var1 = null; 
 var $ var2 = null; 
。 
。 
 public function __construct（$ args）{
 foreach（$ args as $ key => $ value）
 $ this-> $ key = $ value; 
} 
} 
 --------------------- 
 $ args =（$ _SERVER ['REQUEST_METHOD'] ==POST）？ $ _POST：$ _REQUEST; 
 $ obj = new MyClass（$ args）; 
  

上述代码工作正常。请注意，请求参数的名称与类 MyClass 的成员准确映射。

但是我们可以这样做：

  $ class = 我的课; 
 $ obj = new $ class; 
  

如果我们这样做，那么我们可以初始化 $ obj 使用 $ args 。

根据这篇文章， $ obj = $ class 应该工作。但它对我来说并不奏效我试过 get_class_vars（$ obj）。它抛出一个例外。

谢谢

解决方案

一些其他魔法方法：

• __ get（一种在调用对象成员时调用的方法）


• __ set


• __ isset


• __ unset

请参阅此键盘，以便您的代码重写为使用您想要的： / p>

 <？php 
 class MyClass {
 var $ properties = array（）; 
 
 public function __construct（$ args）{
 $ this-> properties = $ args; 
} 
 
 public function __get（$ name）{
 echoGet'$ name'\\\
; 
 if（array_key_exists（$ name，$ this-> properties））{
 return $ this-> properties [$ name]; 
} 
返回null; 
} 
} 
 
 $ args = array（key1=>value1，key2=>value2）; 
 $ class =MyClass; 
 $ obj = new $ class（$ args）; 
 echokey1：。 $ obj-> KEY1; 
？> 
  

Can we dynamically create and initialize an object in PHP? This is the normal code:

class MyClass{
    var $var1 = null;
    var $var2 = null;
    .
    .
    public function __construct($args){
        foreach($args as $key => $value)
            $this->$key = $value;
    }
}
---------------------
$args = ($_SERVER['REQUEST_METHOD'] == "POST") ? $_POST : $_REQUEST;
$obj = new MyClass($args);

The above code works fine. Please note that the names of REQUEST parameters are accurately mapped with the members of class MyClass.

But can we do something like this:

$class = "MyClass";
$obj = new $class;

If we can do like this, then can we initialize $obj by using $args.

According to this post, $obj = $class should work. But it does not work for me. I tried get_class_vars($obj). It threw an exception.

Thanks

解决方案

You have to overload some other magic methods:

• __get (a method that gets called when you call object member)
• __set (a method that gets called when you want to set object member)
• __isset
• __unset

Please see this codepad to see your code rewritten to work with what you want:

<?php
class MyClass{
    var $properties = array();

    public function __construct($args){
        $this->properties = $args;        
    }

    public function __get($name) {
        echo "Getting '$name'\n";
        if (array_key_exists($name, $this->properties)) {
            return $this->properties[$name];
        }
        return null;
    } 
}

$args = array("key1" => "value1", "key2" => "value2");
$class = "MyClass";
$obj = new $class($args);
echo "key1:". $obj->key1;
?>

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