php教程

get_class_vars

(PHP 4, PHP 5, PHP 7)

get_class_vars返回由类的默认属性组成的数组

说明

get_class_vars ( string $class_name ) : array

返回由类的默认公有属性组成的关联数组。

参数

class_name

类名

返回值

Returns an associative array of declared properties visible from the current scope, with their default value. The resulting array elements are in the form of varname => value. In case of an error, it returns FALSE.

更新日志

版本 说明
5.0.3 get_class_vars() will only return the properties that can be accessed from the current scope.
5.0.2 Calling get_class_vars() will now expose all the properties as an array, unlike previous behaviour where protected and private properties were prefixed with nul bytes.
5.0.1 Calling get_class_vars() will expose all properties, as when converting an object to a class.

范例

Example #1 get_class_vars() example

<?php

class myclass {

    var 
$var1// this has no default value...
    
var $var2 "xyz";
    var 
$var3 100;
    private 
$var4;

    
// constructor
    
function __construct() {
        
// change some properties
        
$this->var1 "foo";
        
$this->var2 "bar";
        return 
true;
    }

}

$my_class = new myclass();

$class_vars get_class_vars(get_class($my_class));

foreach (
$class_vars as $name => $value) {
    echo 
"$name : $value\n";
}

?>

以上例程会输出:

var1 :
var2 : xyz
var3 : 100

Example #2 get_class_vars() and scoping behaviour

<?php
function format($array)
{
    return 
implode('|'array_keys($array)) . "\r\n";
}

class 
TestCase
{
    public 
$a    1;
    protected 
$b 2;
    private 
$c   3;

    public static function 
expose()
    {
        echo 
format(get_class_vars(__CLASS__));
    }
}

TestCase::expose();
echo 
format(get_class_vars('TestCase'));
?>

以上例程会输出:

// 5.0.0
a| * b| TestCase c
a| * b| TestCase c

// 5.0.1 - 5.0.2
a|b|c
a|b|c

// 5.0.3 +
a|b|c
a

参见

User Contributed Notes

flobee 16-Nov-2015 12:43
<?php
class someClass {
    public function
toArray() {
       
$records = array();

        foreach(
$this as $key => $value ) {
               
$records[$key] = $value;
        }

        return
$records;
    }

}
?>
bof at bof dot de 09-Sep-2012 07:02
I needed to get only the class static variables, leaving out instance variables.

<?php
function get_static_vars($class) {
   
$result = array();
    foreach (
get_class_vars($class) as $name => $default)
        if (isset(
$class::$$name))
           
$result[$name] = $default;
    return
$result;
}
?>

That function returns only the public ones. The same pattern can be used inside a class, then it returns private and protected static variables, too:

<?php
static protected function get_static_vars($class = NULL) {
    if (!isset(
$class)) $class = get_called_class();
   
$result = array();
    foreach (
get_class_vars($class) as $name => $default)
        if (isset(
$class::$$name))
           
$result[$name] = $default;
    return
$result;
}
?>
Mattias Ahlbck 14-Feb-2012 09:39
get_class_vars_assoc()
- Returns an associative array with name of (parent) class(es) as key(s) and corresponding class vars as sub-arrays. My boilerplate for some crude O/R mapping.

Note: vars re-defined in sub-classes are ignored.

<?php

class GrandClass {
    public
$grandVar;
    public
$in_grand_and_parent;
    public
$in_grand_and_child;
   
   
    public static function
load() {
       
print_r(self::get_class_vars_assoc());
    }
   
    protected static function
get_class_vars_assoc() {
       
$called = get_called_class();
       
//echo "called: $called \n";
       
$classVars[$called] = array_keys(get_class_vars($called));
       
       
$parent = get_parent_class($called);
        while (
$parent !== FALSE ) {
           
//echo "parent: $parent \n";
           
$classVars[$parent] = array_keys(get_class_vars($parent));
           
$classVars[$called] = array_diff($classVars[$called],
                                            
$classVars[$parent]);
            if ( isset(
$prevParentVars) ) {
               
$prevParentVars = array_diff($prevParentVars,
                                            
$classVars[$parent]);
            }
           
           
$prevParentVars = &$classVars[$parent];
           
$parent = get_parent_class($parent);
        }
       
        return
$classVars;
    }
}

class
ParentClass extends GrandClass {
    public
$in_grand_and_parent;
    public
$parentVar;
    public
$in_parent_and_child;
}

class
ChildClass extends ParentClass {
    public
$in_grand_and_child;
    public
$in_parent_and_child;
    public
$childVar;
}

ChildClass::load();

?>

Array
(
    [ChildClass] => Array
        (
            [2] => childVar
        )

    [ParentClass] => Array
        (
            [1] => parentVar
            [2] => in_parent_and_child
        )

    [GrandClass] => Array
        (
            [0] => grandVar
            [1] => in_grand_and_parent
            [2] => in_grand_and_child
        )

)
ciantic 30-Jan-2012 10:06
I propse following for getting Public members, always:
<?PHP
if (!function_exists("get_public_class_vars")) {
    function
get_public_class_vars($class) {
        return
get_class_vars($class);
    }
}
if (!
function_exists("get_public_object_vars")) {
    function
get_public_object_vars($object) {
        return
get_object_vars($object);
    }
}
?>

This is to mitigate the problem and a feature that get_object_vars($this) returns private members. Running it simply outside the scope will get the public.

Iterating public members only and their defaults are enormously useful in e.g. in serialization classes such as options where each public member is an serializable that is saved and loaded.
pBakhuis at Gmail dot com 07-Oct-2011 03:08
If you need the variables before the class is included this function does not seem to work.
Use a reflection class to get around this.
http://www.php.net/reflectionclass
ken at verango dot com 04-Oct-2010 04:50
All 3 of get_object_vars, get_class_vars and reflection getDefaultProperties will reveal the name of the array.  For serialization I recommend:

<?php
$cName
= get_class($this);
$varTemplate= get_class_vars($cName)
foreach (
$varTemplate as $name => $defaultVal) {
 
$vars[$name] = $this->$name; // gets actual val.
}
?>

No scan the $vars and create serialization string how you wish.

This protects against erroneous prior deserializing in maintaining the integrity of the class template and ignoring unintended object properties.
ianitsky at gmail dot com 10-Nov-2009 11:53
If you need get the child protected/private vars ignoring the parent vars, use like this:

<?php
class childClass extends parentClass {
    private
$login;
    private
$password;
   
    public function
__set($key, $val) {
        if (
$key == 'password')
           
$this->$key = md5($val);
        else
           
$this->$key = $val;
    }
}
class
parentClass {
    public
$name;
    public
$email;
   
    function
__construct() {
       
$reflection = new ReflectionClass($this);
       
$vars = array_keys($reflection->getdefaultProperties());
       
$reflection = new ReflectionClass(__CLASS__);
       
$parent_vars = array_keys($reflection->getdefaultProperties());
       
       
$my_child_vars = array();
        foreach (
$vars as $key) {
            if (!
in_array($key, $parent_vars)) {
               
$my_child_vars[] = $key;
            }
        }
       
       
print_r($my_child_vars);
    }
}

$child_class = new childClass();
?>
harmor 20-Dec-2008 03:53
So I wanted to get a list of the public parameters in a child class using a static function pre-5.3.0 (< 5.3.0).  In 5.3.0+ you would use the new 'static' like you would 'self' to get the late binding.

<?php
class childClass extends parentClass
{
    public
$id;
    public
$name;   

    public static function
getFields()
    {
        return
self::_getFields(__CLASS__);
    }
   
}
abstract class
parentClass
{
    public
$idInParent;
    public
$nameInParent;
   
    abstract public static function
getFields();
   
    final protected static function
_getFields($className)
    {
       
$rtn = array();
        foreach (
array_keys(get_class_vars($className)) as $var) {
           
$rtn[] = $var;           
        }
        return
$rtn;
    }
   
}

var_dump(childClass::getFields());
?>

Results:
array(4) {
  [0]=>
  string(2) "id"
  [1]=>
  string(4) "name"
  [2]=>
  string(10) "idInParent"
  [3]=>
  string(12) "nameInParent"
}
artktec at art-k-tec dot com 16-Nov-2007 09:18
There seems to be be a function to get constants missing , i.e. get_class_constants() ... so here is a simple function for you all. Hopefully Zend will include this in the next round as a native php call, without using reflection.

<?php
  
function GetClassConstants($sClassName) {
     
$oClass = new ReflectionClass($sClassName);
      return
$oClass->getConstants());
   }
?>
phpnet at stccorp dot net 15-Jun-2007 05:18
This is one of the best php functions. Look at what you can do

class Object
{
   var $updtFields;//keep track of affected values
   function Object($record="") {
       if (is_array($record))
       {
          $this->updtFields = array();
          foreach(array_keys(get_class_vars(get_class($this))) as $k)
          if (isset($record[$k]))
         {
          $this->$k = $record[$k];
          $this->updtFields[] = $k;
         }
      }   
   }//end of arrayToObject
      
   function toDebug($nl='<br>')
   {
       foreach(array_keys(get_class_vars(get_class($this))) as $k)
       echo "$k = [" . $this->$k . "]{$nl}";
    }//end of toDebug 
}

Now you can do really cool things. If you have a form like
<form action="" method="post">
  <input type="text" name="name" />
  <input type="text" name="phone" />
  <input type="submit" />
</form>

and you define your class like this
class Person extends Object{
  var $name; //same same as in the form
  var $phone;
}

when you submmit the form, you can get the data like

$person = new Person($_POST);

//everything in just one line,cool!! Also if you use pear db or adodb when you get data from the database you can do the same thing except use the $row that you get from the database. Remember to ask the result is associative mode.

This is my core Object for everthing I do and it works great.
bernd at tiggerswelt dot net 29-Jan-2007 02:52
If you assign a constant value using the self-scope by default to a variable, get_class_vars() will result in a FATAL error.

Example:

<?PHP

 
class Foo {
    const
Bar = "error";
   
    public
$Foo = self::Bar;
  }
 
 
print_r(get_class_vars("Foo"));

?>

... but using "Foo::Bar" instead "self::Bar" will work ;)
gizmobits at hotmail dot com 03-Mar-2006 07:48
I wanted a simple ToString() function that was automatic and class independent.  I wanted to dump it into any of several classes and get values quickly.  I wanted to leave it there so I could customize it for each class, so an outside function wasn't suitable.  I came up with this and thought it might be useful.  Have fun!

<?php
 
function ToString () {
   
$s = "";
   
$s .= "<table>\n";
   
$s .= "<tr><td colspan=2><hr></td></tr>\n";
    foreach (
get_class_vars(get_class($this)) as $name => $value) {
     
$s .= "<tr><td>$name:</td><td>" . $this->$name . "</td></tr>\n";
    }
   
$s .= "<tr><td colspan=2><hr></td></tr>\n";
   
$s .= "</table>\n";
    return
$s;
  }

?>
php dot net at sharpdreams dot com 25-Oct-2005 06:25
Contrary to multiple comments throughout the manual, get_class_vars() performed within a class can access any public, protected, and private members.

<?php
class Foo {
   public
$x;
   protected
$y;
   private
$z;
   public function
__sleep() {
      return(
get_class_vars( __CLASS__ ) );
   }
}
?>

works fine (returns x, y, & z). However, given the same class as above,

<?php
print_r
( get_class_vars( "Foo" ) );
?>

will NOT return x, y, & z. Instead it will only return the public members (in our case, z).
alan_k at php dot net 21-Jan-2005 07:23
in PHP5 to get all the vars (including private etc.) use:

$reflection = new ReflectionClass($class);
$defaults = $reflection->getdefaultProperties();
rec at NOSPAM dot instantmassacre dot com 23-Jan-2003 04:23
If you want to retrieve the class vars from within the class itself, use $this.

<?php
class Foo {

    var
$a;
    var
$b;
    var
$c;
    var
$d;
    var
$e;

    function
GetClassVars()
    {
        return
array_keys(get_class_vars(get_class($this))); // $this
   
}

}

$Foo = new Foo;

$class_vars = $Foo->GetClassVars();

foreach (
$class_vars as $cvar)
{
    echo
$cvar . "<br />\n";
}
?>

Produces, after PHP 4.2.0, the following:

a
b
c
d
e

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