这里有一种优雅的方法。创建trait，在给定参数数量的情况下启用多个构造函数。你只需将参数的数量添加到函数名“__construct”中。所以一个参数是"__construct1"，两个"__construct2"…等。

trait constructable
{
    public function __construct() 
    { 
        $a = func_get_args(); 
        $i = func_num_args(); 
        if (method_exists($this,$f='__construct'.$i)) { 
            call_user_func_array([$this,$f],$a); 
        } 
    } 
}

class a{
    use constructable;

    public $result;

    public function __construct1($a){
        $this->result = $a;
    }

    public function __construct2($a, $b){
        $this->result =  $a + $b;
    }
}

echo (new a(1))->result;    // 1
echo (new a(1,2))->result;  // 3

我知道我在这方面非常晚，但我提出了一个相当灵活的模式，应该允许一些真正有趣和通用的实现。

像往常一样设置类，使用您喜欢的任何变量。

class MyClass{ protected $myVar1; protected $myVar2; public function __construct($obj = null){ if($obj){ foreach (((object)$obj) as $key => $value) { if(isset($value) && in_array($key, array_keys(get_object_vars($this)))){ $this->$key = $value; } } } } } When you make your object just pass an associative array with the keys of the array the same as the names of your vars, like so... $sample_variable = new MyClass([ 'myVar2'=>123, 'i_dont_want_this_one'=> 'This won\'t make it into the class' ]); print_r($sample_variable); The print_r($sample_variable); after this instantiation yields the following: MyClass Object ( [myVar1:protected] => [myVar2:protected] => 123 ) Because we've initialize $group to null in our __construct(...), it is also valid to pass nothing whatsoever into the constructor as well, like so... $sample_variable = new MyClass(); print_r($sample_variable); Now the output is exactly as expected: MyClass Object ( [myVar1:protected] => [myVar2:protected] => ) The reason I wrote this was so that I could directly pass the output of json_decode(...) to my constructor, and not worry about it too much. This was executed in PHP 7.1. Enjoy!

这是我对它的看法(为php 5.6构建)。

它将查看构造函数参数类型(数组，类名，无描述)并比较给定的参数。构造函数必须在最后以最少的特异性给出。例子:

// demo class
class X {
    public $X;

    public function __construct($x) {
        $this->X = $x;
    }

    public function __toString() {
        return 'X'.$this->X;
    }
}

// demo class
class Y {
    public $Y;

    public function __construct($y) {
        $this->Y = $y;
    }
    public function __toString() {
        return 'Y'.$this->Y;
    }
}

// here be magic
abstract class MultipleConstructors {
    function __construct() {
        $__get_arguments       = func_get_args();
        $__number_of_arguments = func_num_args();

        $__reflect = new ReflectionClass($this);
        foreach($__reflect->getMethods() as $__reflectmethod) {
            $__method_name = $__reflectmethod->getName();
            if (substr($__method_name, 0, strlen('__construct')) === '__construct') {
                $__parms = $__reflectmethod->getParameters();
                if (count($__parms) == $__number_of_arguments) {
                    $__argsFit = true;
                    foreach ($__parms as $__argPos => $__param) {
                        $__paramClass= $__param->getClass();
                        $__argVar = func_get_arg($__argPos);
                        $__argVarType = gettype($__argVar);
                        $__paramIsArray = $__param->isArray() == true;
                        $__argVarIsArray = $__argVarType == 'array';
                        // parameter is array and argument isn't, or the other way around.
                        if (($__paramIsArray && !$__argVarIsArray) ||
                            (!$__paramIsArray && $__argVarIsArray)) {
                            $__argsFit = false;
                            continue;
                        }
                        // class check
                        if ((!is_null($__paramClass) && $__argVarType != 'object') ||
                            (is_null($__paramClass) && $__argVarType == 'object')){
                            $__argsFit = false;
                            continue;
                        }
                        if (!is_null($__paramClass) && $__argVarType == 'object') {
                            // class type check
                            $__paramClassName = "N/A";
                            if ($__paramClass)
                                $__paramClassName = $__paramClass->getName();
                            if ($__paramClassName != get_class($__argVar)) {
                                $__argsFit = false;
                            }
                        }
                    }
                    if ($__argsFit) {
                        call_user_func_array(array($this, $__method_name), $__get_arguments);
                        return;
                    }
                }
            }
        }
        throw new Exception("No matching constructors");
    }
}

// how to use multiple constructors
class A extends MultipleConstructors {
    public $value;

    function __constructB(array $hey) {
        $this->value = 'Array#'.count($hey).'<br/>';
    }
    function __construct1(X $first) {
        $this->value = $first .'<br/>';
    }

    function __construct2(Y $second) {
        $this->value = $second .'<br/>';
    }
    function __constructA($hey) {
        $this->value = $hey.'<br/>';
    }

    function __toString() {
        return $this->value;
    }
}

$x = new X("foo");
$y = new Y("bar");

$aa = new A(array("one", "two", "three"));
echo $aa;

$ar = new A("baz");
echo $ar;

$ax = new A($x);
echo $ax;

$ay = new A($y);
echo $ay;

结果:

Array#3
baz
Xfoo
Ybar

如果没有找到构造函数，可以将其删除并允许构造函数为“空”，而不是终止异常。或者你喜欢什么都行。

正如在其他评论中所述，由于PHP不支持重载，通常会避免构造函数中的“类型检查技巧”，而是使用工厂模式

ie.

$myObj = MyClass::factory('fromInteger', $params);
$myObj = MyClass::factory('fromRow', $params);

你总是可以在构造函数中添加一个额外的参数，比如mode，然后对它执行一个switch语句……

class myClass 
{
    var $error ;
    function __construct ( $data, $mode )
    {
        $this->error = false
        switch ( $mode )
        {
            'id' : processId ( $data ) ; break ;
            'row' : processRow ( $data ); break ;
            default : $this->error = true ; break ;
         }
     }

     function processId ( $data ) { /* code */ }
     function processRow ( $data ) { /* code */ }
}

$a = new myClass ( $data, 'id' ) ;
$b = new myClass ( $data, 'row' ) ;
$c = new myClass ( $data, 'something' ) ;

if ( $a->error )
   exit ( 'invalid mode' ) ;
if ( $b->error )
   exit ('invalid mode' ) ;
if ( $c->error )
   exit ('invalid mode' ) ;

Also with that method at any time if you wanted to add more functionality you can just add another case to the switch statement, and you can also check to make sure someone has sent the right thing through - in the above example all the data is ok except for C as that is set to "something" and so the error flag in the class is set and control is returned back to the main program for it to decide what to do next (in the example I just told it to exit with an error message "invalid mode" - but alternatively you could loop it back round until valid data is found).

你可以像下面这样做，非常简单明了:

public function __construct()    
{
   $arguments = func_get_args(); 

   switch(sizeof(func_get_args()))      
   {
    case 0: //No arguments
        break; 
    case 1: //One argument
        $this->do_something($arguments[0]); 
        break;              
    case 2:  //Two arguments
        $this->do_something_else($arguments[0], $arguments[1]); 
        break;            
   }
}