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

<?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";}?>