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

<?phpclass 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( $product ) == 'CdProduct' ) { print "\$product is a CdProduct object\n";}?><?phpclass CdProduct {}function getProduct() { return new CdProduct( "Exile on Coldharbour Lane", "The", "Alabama 3", 10.99, 60.33 );}$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。

<?phpclass 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

<?phpclass 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 nameprint $product->$method(); // invoke the methodif ( 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:

titletitletitletitleArray( [coverUrl] =>)CdProduct is a subclass of ShopProductCdProduct is a subclass of incidentalCdProduct is an interface of incidental

__call方法

<?phpclass 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

<?phpclass 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

<?phpclass 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 $this->price; }}?><?phprequire_once "fullshop.php";$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

<?phprequire_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

<?phprequire_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 definedgetPlayLength is public----getSummaryLine is user definedgetSummaryLine is public----getProducerFirstName is user definedgetProducerFirstName is public----getProducerMainName is user definedgetProducerMainName is public----setDiscount is user definedsetDiscount is public----getDiscount is user definedgetDiscount is public----getTitle is user definedgetTitle is public----getPrice is user definedgetPrice is public----getProducer is user definedgetProducer is public

获取构造函数参数情况

<?phprequire_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

更多关于PHP相关内容感兴趣的读者可查看本站专题：《php面向对象程序设计入门教程》、《PHP基本语法入门教程》、《PHP运算与运算符用法总结》、《PHP网络编程技巧总结》、《PHP数组(Array)操作技巧大全》、《php字符串(string)用法总结》、《php+mysql数据库操作入门教程》及《php常见数据库操作技巧汇总》

希望本文所述对大家PHP程序设计有所帮助。