PHP面向对象程序设计之类与反射API详解

本文实例讲述了PHP面向对象程序设计之类与反射API。分享给大家供大家参考，具体如下：

了解类

class_exists验证类是否存在

<?php
// TaskRunner.php
$classname = "Task";
$path = "tasks/{$classname}.php";
if ( ! file_exists( $path ) ) {
  throw new Exception( "No such file as {$path}" ); //抛出异常,类文件不存在
}
require_once( $path );
$qclassname = "tasks\\$classname";
if ( ! class_exists( $qclassname ) ) {
  throw new Exception( "No such class as $qclassname" ); //抛出异常,类不存在Fatal error: Uncaught exception 'Exception' with message 'No such class as tasks\Task'
Stack trace:
#0 {main}
}
$myObj = new $qclassname();
$myObj->doSpeak();
?>

get_class 检查对象的类 instanceof 验证对象是否属于某个类

<?php
class CdProduct {}
function getProduct() {
  return new CdProduct(  "Exile on Coldharbour Lane",
                "The", "Alabama 3", 10.99, 60.33 ); // 返回一个类对象
}
$product = getProduct();
if ( get_class( $product ) == 'CdProduct' ) {
  print "\$product is a CdProduct object\n";
}
?>
<?php
class CdProduct {}
function getProduct() {
  return new CdProduct(  "Exile on Coldharbour Lane",
                "The", "Alabama 3", 10.99, 60.33 );
}
$product = getProduct();
if ( $product instanceof CdProduct ) {
  print "\$product is a CdProduct object\n";
}
?>

get_class_methods 得到类中所有的方法列表,只获取public的方法，protected，private的方法获取不到。默认的就是public。

<?php
class CdProduct {
  function __construct() { }
  function getPlayLength() { }
  function getSummaryLine() { }
  function getProducerFirstName() { }
  function getProducerMainName() { }
  function setDiscount() { }
  function getDiscount() { }
  function getTitle() { }
  function getPrice() { }
  function getProducer() { }
}
print_r( get_class_methods( 'CdProduct' ) );
?>

output:

Array
(
  [0] => __construct
  [1] => getPlayLength
  [2] => getSummaryLine
  [3] => getProducerFirstName
  [4] => getProducerMainName
  [5] => setDiscount
  [6] => getDiscount
  [7] => getTitle
  [8] => getPrice
  [9] => getProducer
)

更多验证

<?php
class ShopProduct {}
interface incidental {};
class CdProduct extends ShopProduct implements incidental {
  public $coverUrl;
  function __construct() { }
  function getPlayLength() { }
  function getSummaryLine() { }
  function getProducerFirstName() { }
  function getProducerMainName() { }
  function setDiscount() { }
  function getDiscount() { }
  function getTitle() { return "title\n"; }
  function getPrice() { }
  function getProducer() { }
}
function getProduct() {
  return new CdProduct();
}
$product = getProduct(); // acquire an object
$method = "getTitle";   // define a method name
print $product->$method(); // invoke the method
if ( in_array( $method, get_class_methods( $product ) ) ) {
  print $product->$method(); // invoke the method
}
if ( is_callable( array( $product, $method) ) ) {
  print $product->$method(); // invoke the method
}
if ( method_exists( $product, $method ) ) {
  print $product->$method(); // invoke the method
}
print_r( get_class_vars( 'CdProduct' ) );
if ( is_subclass_of( $product, 'ShopProduct' ) ) {
  print "CdProduct is a subclass of ShopProduct\n";
}
if ( is_subclass_of( $product, 'incidental' ) ) {
  print "CdProduct is a subclass of incidental\n";
}
if ( in_array( 'incidental', class_implements( $product )) ) {
  print "CdProduct is an interface of incidental\n";
}
?>

output:

title
title
title
title
Array
(
  [coverUrl] =>
)
CdProduct is a subclass of ShopProduct
CdProduct is a subclass of incidental
CdProduct is an interface of incidental

__call方法

<?php
class OtherShop {
  function thing() {
    print "thing\n";
  }
  function andAnotherthing() {
    print "another thing\n";
  }
}
class Delegator {
  private $thirdpartyShop;
  function __construct() {
    $this->thirdpartyShop = new OtherShop();
  }
  function __call( $method, $args ) { // 当调用未命名方法时执行call方法
    if ( method_exists( $this->thirdpartyShop, $method ) ) {
      return $this->thirdpartyShop->$method( );
    }
  }
}
$d = new Delegator();
$d->thing();
?>

output:

thing

传参使用

<?php
class OtherShop {
  function thing() {
    print "thing\n";
  }
  function andAnotherthing( $a, $b ) {
    print "another thing ($a, $b)\n";
  }
}
class Delegator {
  private $thirdpartyShop;
  function __construct() {
    $this->thirdpartyShop = new OtherShop();
  }
  function __call( $method, $args ) {
    if ( method_exists( $this->thirdpartyShop, $method ) ) {
      return call_user_func_array(
            array( $this->thirdpartyShop,
              $method ), $args );
    }
  }
}
$d = new Delegator();
$d->andAnotherThing( "hi", "hello" );
?>

output:

another thing (hi, hello)

反射API

fullshop.php

<?php
class ShopProduct {
  private $title;
  private $producerMainName;
  private $producerFirstName;
  protected $price;
  private $discount = 0;
  public function __construct(  $title, $firstName,
              $mainName, $price ) {
    $this->title       = $title;
    $this->producerFirstName = $firstName;
    $this->producerMainName = $mainName;
    $this->price       = $price;
  }
  public function getProducerFirstName() {
    return $this->producerFirstName;
  }
  public function getProducerMainName() {
    return $this->producerMainName;
  }
  public function setDiscount( $num ) {
    $this->discount=$num;
  }
  public function getDiscount() {
    return $this->discount;
  }
  public function getTitle() {
    return $this->title;
  }
  public function getPrice() {
    return ($this->price - $this->discount);
  }
  public function getProducer() {
    return "{$this->producerFirstName}".
        " {$this->producerMainName}";
  }
  public function getSummaryLine() {
    $base = "{$this->title} ( {$this->producerMainName}, ";
    $base .= "{$this->producerFirstName} )";
    return $base;
  }
}
class CdProduct extends ShopProduct {
  private $playLength = 0;
  public function __construct(  $title, $firstName,
              $mainName, $price, $playLength=78 ) {
    parent::__construct(  $title, $firstName,
                $mainName, $price );
    $this->playLength = $playLength;
  }
  public function getPlayLength() {
    return $this->playLength;
  }
  public function getSummaryLine() {
    $base = parent::getSummaryLine();
    $base .= ": playing time - {$this->playLength}";
    return $base;
  }
}
class BookProduct extends ShopProduct {
  private $numPages = 0;
  public function __construct(  $title, $firstName,
              $mainName, $price, $numPages ) {
    parent::__construct(  $title, $firstName,
                $mainName, $price );
    $this->numPages = $numPages;
  }
  public function getNumberOfPages() {
    return $this->numPages;
  }
  public function getSummaryLine() {
    $base = parent::getSummaryLine();
    $base .= ": page count - {$this->numPages}";
    return $base;
  }
  public function getPrice() {
    return $this->price;
  }
}
/*
$product1 = new CdProduct("cd1", "bob", "bobbleson", 4, 50 );
print $product1->getSummaryLine()."\n";
$product2 = new BookProduct("book1", "harry", "harrelson", 4, 30 );
print $product2->getSummaryLine()."\n";
*/
?>
<?php
require_once "fullshop.php";
$prod_class = new ReflectionClass( 'CdProduct' );
Reflection::export( $prod_class );
?>

output:

Class [ <user> class CdProduct extends ShopProduct ] {
 @@ D:\xampp\htdocs\popp-code\5\fullshop.php 53-73
 - Constants [0] {
 }
 - Static properties [0] {
 }
 - Static methods [0] {
 }
 - Properties [2] {
  Property [ <default> private $playLength ]
  Property [ <default> protected $price ]
 }
 - Methods [10] {
  Method [ <user, overwrites ShopProduct, ctor> public method __construct ] {
   @@ D:\xampp\htdocs\popp-code\5\fullshop.php 56 - 61
   - Parameters [5] {
    Parameter #0 [ <required> $title ]
    Parameter #1 [ <required> $firstName ]
    Parameter #2 [ <required> $mainName ]
    Parameter #3 [ <required> $price ]
    Parameter #4 [ <optional> $playLength = 78 ]
   }
  }
  Method [ <user> public method getPlayLength ] {
   @@ D:\xampp\htdocs\popp-code\5\fullshop.php 63 - 65
  }
  Method [ <user, overwrites ShopProduct, prototype ShopProduct> public method getSummaryLine ] {
   @@ D:\xampp\htdocs\popp-code\5\fullshop.php 67 - 71
  }
  Method [ <user, inherits ShopProduct> public method getProducerFirstName ] {
   @@ D:\xampp\htdocs\popp-code\5\fullshop.php 17 - 19
  }
  Method [ <user, inherits ShopProduct> public method getProducerMainName ] {
   @@ D:\xampp\htdocs\popp-code\5\fullshop.php 21 - 23
  }
  Method [ <user, inherits ShopProduct> public method setDiscount ] {
   @@ D:\xampp\htdocs\popp-code\5\fullshop.php 25 - 27
   - Parameters [1] {
    Parameter #0 [ <required> $num ]
   }
  }
  Method [ <user, inherits ShopProduct> public method getDiscount ] {
   @@ D:\xampp\htdocs\popp-code\5\fullshop.php 29 - 31
  }
  Method [ <user, inherits ShopProduct> public method getTitle ] {
   @@ D:\xampp\htdocs\popp-code\5\fullshop.php 33 - 35
  }
  Method [ <user, inherits ShopProduct> public method getPrice ] {
   @@ D:\xampp\htdocs\popp-code\5\fullshop.php 37 - 39
  }
  Method [ <user, inherits ShopProduct> public method getProducer ] {
   @@ D:\xampp\htdocs\popp-code\5\fullshop.php 41 - 44
  }
 }
}

点评：把类看的透彻的一塌糊涂，比var_dump强多了。哪些属性，继承了什么类。类中的方法哪些是自己的，哪些是重写的，哪些是继承的，一目了然。

查看类数据

<?php
require_once("fullshop.php");
function classData( ReflectionClass $class ) {
 $details = "";
 $name = $class->getName();
 if ( $class->isUserDefined() ) {
  $details .= "$name is user defined\n";
 }
 if ( $class->isInternal() ) {
  $details .= "$name is built-in\n";
 }
 if ( $class->isInterface() ) {
  $details .= "$name is interface\n";
 }
 if ( $class->isAbstract() ) {
  $details .= "$name is an abstract class\n";
 }
 if ( $class->isFinal() ) {
  $details .= "$name is a final class\n";
 }
 if ( $class->isInstantiable() ) {
  $details .= "$name can be instantiated\n";
 } else {
  $details .= "$name can not be instantiated\n";
 }
 return $details;
}
$prod_class = new ReflectionClass( 'CdProduct' );
print classData( $prod_class );
?>

output:

CdProduct is user defined
CdProduct can be instantiated

查看方法数据

<?php
require_once "fullshop.php";
$prod_class = new ReflectionClass( 'CdProduct' );
$methods = $prod_class->getMethods();
foreach ( $methods as $method ) {
 print methodData( $method );
 print "\n----\n";
}
function methodData( ReflectionMethod $method ) {
 $details = "";
 $name = $method->getName();
 if ( $method->isUserDefined() ) {
  $details .= "$name is user defined\n";
 }
 if ( $method->isInternal() ) {
  $details .= "$name is built-in\n";
 }
 if ( $method->isAbstract() ) {
  $details .= "$name is abstract\n";
 }
 if ( $method->isPublic() ) {
  $details .= "$name is public\n";
 }
 if ( $method->isProtected() ) {
  $details .= "$name is protected\n";
 }
 if ( $method->isPrivate() ) {
  $details .= "$name is private\n";
 }
 if ( $method->isStatic() ) {
  $details .= "$name is static\n";
 }
 if ( $method->isFinal() ) {
  $details .= "$name is final\n";
 }
 if ( $method->isConstructor() ) {
  $details .= "$name is the constructor\n";
 }
 if ( $method->returnsReference() ) {
  $details .= "$name returns a reference (as opposed to a value)\n";
 }
 return $details;
}
?>

output:

__construct is user defined
__construct is public
__construct is the constructor
----
getPlayLength is user defined
getPlayLength is public
----
getSummaryLine is user defined
getSummaryLine is public
----
getProducerFirstName is user defined
getProducerFirstName is public
----
getProducerMainName is user defined
getProducerMainName is public
----
setDiscount is user defined
setDiscount is public
----
getDiscount is user defined
getDiscount is public
----
getTitle is user defined
getTitle is public
----
getPrice is user defined
getPrice is public
----
getProducer is user defined
getProducer is public

获取构造函数参数情况

<?php
require_once "fullshop.php";
$prod_class = new ReflectionClass( 'CdProduct' );
$method = $prod_class->getMethod( "__construct" );
$params = $method->getParameters();
foreach ( $params as $param ) {
  print argData( $param )."\n";
}
function argData( ReflectionParameter $arg ) {
 $details = "";
 $declaringclass = $arg->getDeclaringClass();
 $name = $arg->getName();
 $class = $arg->getClass();
 $position = $arg->getPosition();
 $details .= "\$$name has position $position\n";
 if ( ! empty( $class ) ) {
  $classname = $class->getName();
  $details .= "\$$name must be a $classname object\n";
 }
 if ( $arg->isPassedByReference() ) {
  $details .= "\$$name is passed by reference\n";
 }
 if ( $arg->isDefaultValueAvailable() ) {
  $def = $arg->getDefaultValue();
  $details .= "\$$name has default: $def\n";
 }
 if ( $arg->allowsNull() ) {
  $details .= "\$$name can be null\n";
 }
 return $details;
}
?>

output:

$title has position 0
$title can be null
$firstName has position 1
$firstName can be null
$mainName has position 2
$mainName can be null
$price has position 3
$price can be null
$playLength has position 4
$playLength has default: 78
$playLength can be null

希望本文所述对大家PHP程序设计有所帮助。