blocks|key|835784|text|可以，停那儿吧!|type|unstyled|depth|inlineStyleRanges|entityRanges|data|835785|$str+=+'One';
$class+=+'Class'.$str;
$object+=+new+$class();|code-block|syntax|javascript|835786|使用命名空间时，请提供fully+qualified+name|offset|length|835787|$class+=+'\Foo\Bar\MyClass';+
$instance+=+new+$class();|835788|你可以在php中做的其他很酷的事情有：|835789|Variable+variables|835790|$personCount+=+123;
$varname+=+'personCount';
echo+$$varname;+//+echo's+123|835791|和可变函数和方法。|835792|$func+=+'my_function';
$func('param1');+//+calls+my_function('param1');

$method+=+'doStuff';
$object+=+new+MyClass();
$object->$method();+//+calls+the+MyClass->doStuff()+method.+|835793|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/manual/en/language.namespaces.rules.php|1|http://php.net/manual/en/language.variables.variable.php^0|0|0|B|K|0|0|0|0|0|I|1|0|0|0|0^^$0|@$1|2|3|4|5|6|7|16|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|17|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|18|8|@]|9|@$I|19|J|1A|1|1B]]|A|$]]|$1|K|3|L|5|D|7|1C|8|@]|9|@]|A|$E|F]]|$1|M|3|N|5|6|7|1D|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|1E|8|@]|9|@$I|1F|J|1G|1|1H]]|A|$]]|$1|Q|3|R|5|D|7|1I|8|@]|9|@]|A|$E|F]]|$1|S|3|T|5|6|7|1J|8|@]|9|@]|A|$]]|$1|U|3|V|5|D|7|1K|8|@]|9|@]|A|$E|F]]|$1|W|3|-4|5|6|7|1L|8|@]|9|@]|A|$]]]|X|$Y|$5|Z|10|11|A|$12|13]]|14|$5|Z|10|11|A|$12|15]]]]

Yes, you can!

<pre><code>$str = 'One';
$class = 'Class'.$str;
$object = new $class();
</code></pre>

When using namespaces, supply the <a href="http://php.net/manual/en/language.namespaces.rules.php" rel="noreferrer">fully qualified name</a>:

<pre><code>$class = '\Foo\Bar\MyClass'; 
$instance = new $class();
</code></pre>

Other cool stuff you can do in php are: 
<a href="http://php.net/manual/en/language.variables.variable.php" rel="noreferrer">Variable variables</a>:

<pre><code>$personCount = 123;
$varname = 'personCount';
echo $$varname; // echo's 123
</code></pre>

And variable functions &amp; methods.

<pre><code>$func = 'my_function';
$func('param1'); // calls my_function('param1');

$method = 'doStuff';
$object = new MyClass();
$object-&gt;$method(); // calls the MyClass-&gt;doStuff() method. 
</code></pre>

blocks|key|1050597|text|看一下来自http://www.php.net/manual/en/language.oop5.basic.php的示例3|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1050598|$className+=+'Foo';
$instance+=+new+$className();+//+Foo()|code-block|syntax|javascript|1050599|entityMap|0|LINK|mutability|MUTABLE|url|http://www.php.net/manual/en/language.oop5.basic.php^0|5|1G|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

have a look at example 3 from <a href="http://www.php.net/manual/en/language.oop5.basic.php" rel="noreferrer">http://www.php.net/manual/en/language.oop5.basic.php</a>

<pre><code>$className = 'Foo';
$instance = new $className(); // Foo()
</code></pre>

blocks|key|1050667|text|您可以简单地使用以下语法来创建一个新类(如果您正在创建一个factory，这将非常方便)：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1050668|$className+=+$whatever;
$object+=+new+$className;|code-block|syntax|javascript|1050669|作为一个(异常粗糙的)工厂方法示例：|1050670|public+function+&factory($className)+{

++++require_once($className+.+'.php');
++++if(class_exists($className))+return+new+$className;

++++die('Cannot+create+new+"'+.+$className+.+'"+class+-+includes+not+found+or+class+unavailable.');
}|1050671|entityMap|0|LINK|mutability|MUTABLE|url|http://en.wikipedia.org/wiki/Factory_method_pattern^0|T|7|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

You can simply use the following syntax to create a new class (this is handy if you're creating a <a href="http://en.wikipedia.org/wiki/Factory_method_pattern" rel="noreferrer">factory</a>):

<pre><code>$className = $whatever;
$object = new $className;
</code></pre>

As an (exceptionally crude) example factory method:

<pre><code>public function &amp;factory($className) {

 require_once($className . '.php');
 if(class_exists($className)) return new $className;

 die('Cannot create new "' . $className . '" class - includes not found or class unavailable.');
}
</code></pre>

blocks|key|836008|text|假设ClassOne被定义为：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|836009|public+class+ClassOne
{
++++protected+$arg1;
++++protected+$arg2;

++++//Contructor
++++public+function+__construct($arg1,+$arg2)
++++{
++++++++$this->arg1+=+$arg1;
++++++++$this->arg2+=+$arg2;
++++}

++++public+function+echoArgOne
++++{
++++++++echo+$this->arg1;
++++}

}|code-block|syntax|javascript|836010|使用PHP反射；|836011|$str+=+"One";
$className+=+"Class".$str;
$class+=+new+\ReflectionClass($className);|836012|创建一个新实例：|836013|$instance+=+$class->newInstanceArgs(["Banana",+"Apple")]);|836014|调用一个方法：|836015|$instance->echoArgOne();
//prints+"Banana"|836016|使用变量作为方法：|836017|$method+=+"echoArgOne";
$instance->$method();

//prints+"Banana"|836018|使用反射而不是仅仅使用原始字符串来创建对象可以让您更好地控制对象并简化可测试性(PHPUnit在很大程度上依赖于反射)|836019|entityMap^0|2|8|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@$9|15|A|16|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|17|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|18|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|19|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1A|8|@]|D|@]|E|$]]|$1|Q|3|R|5|H|7|1B|8|@]|D|@]|E|$I|J]]|$1|S|3|T|5|6|7|1C|8|@]|D|@]|E|$]]|$1|U|3|V|5|H|7|1D|8|@]|D|@]|E|$I|J]]|$1|W|3|X|5|6|7|1E|8|@]|D|@]|E|$]]|$1|Y|3|Z|5|H|7|1F|8|@]|D|@]|E|$I|J]]|$1|10|3|11|5|6|7|1G|8|@]|D|@]|E|$]]|$1|12|3|-4|5|6|7|1H|8|@]|D|@]|E|$]]]|13|$]]

Lets say <code>ClassOne</code> is defined as:

<pre><code>public class ClassOne
{
 protected $arg1;
 protected $arg2;

 //Contructor
 public function __construct($arg1, $arg2)
 {
 $this-&gt;arg1 = $arg1;
 $this-&gt;arg2 = $arg2;
 }

 public function echoArgOne
 {
 echo $this-&gt;arg1;
 }

}
</code></pre>

Using PHP Reflection;

<pre><code>$str = "One";
$className = "Class".$str;
$class = new \ReflectionClass($className);
</code></pre>

Create a new Instance:

<pre><code>$instance = $class-&gt;newInstanceArgs(["Banana", "Apple")]);
</code></pre>

Call a method:

<pre><code>$instance-&gt;echoArgOne();
//prints "Banana"
</code></pre>

Use a variable as a method:

<pre><code>$method = "echoArgOne";
$instance-&gt;$method();

//prints "Banana"
</code></pre>

Using Reflection instead of just using the raw string to create an object gives you better control over your object and easier testability (PHPUnit relies heavily on Reflection)

I have two classes, <code>class ClassOne { }</code> and <code>class ClassTwo {}</code>. I am getting a string which can be either <code>"One"</code> or <code>"Two"</code>.

Instead of using a long <code>switch</code> statement such as:

<pre><code>switch ($str) {
 case "One":
 return new ClassOne();
 case "Two":
 return new ClassTwo();
}
</code></pre>

Is there a way I can create an instance using a string, i.e. <code>new Class("Class" . $str);</code>?

Creating PHP class instance with a string

我有两个类，class ClassOne { }和class ClassTwo {}。我得到了一个可以是"One"或"Two"的字符串。而不是使用长switch语句，例如：switch ($str) {    case "One":        return new ClassOne();    case "Two"...

问使用字符串创建PHP类实例
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