php面向对象中一些类的代码实例汇总

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)

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