Detailed explanation of PHP object-oriented programming and reflection API
- 高洛峰Original
- 2016-12-30 10:14:231323browse
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。
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