PHP面向对象程序设计之命名空间与自动加载类详解

<?php
require_once "useful/Outputter.php";
class Outputter {
  // output data
  private $name;
  public function setName($name) {
    $this->name = $name;
  }
  public function getName() {
    return $this->name;
  }
}
$obj = new Outputter(); // 同一命名空间下,类名不能相同,默认命名空间为空。空也是一种命名空间。
$obj -> setName("Jack");
print $obj->getName();
//namespace useful; // 更改命名空间，否则查询不到Hello类,Fatal error: Class 'my\Hello' not found
$hello = new Hello();
?>
<?php
// useful/Outputter.php
namespace useful; // 命名空间
class Outputter {
  //
}
class Hello {
}
?>

<?php
namespace com\getinstance\util;
class Debug {
  static function helloWorld() {
    print "hello from Debug\n";
  }
}
namespace main;
// com\getinstance\util\Debug::helloWorld(); // 找不到Debug类
\com\getinstance\util\Debug::helloWorld(); // 加斜杠之后，就从根部去寻找了。
// outPut:hello from Debug
?>

<?php
namespace com\getinstance\util;
class Debug {
  static function helloWorld() {
    print "hello from Debug\n";
  }
}
namespace main;
use com\getinstance\util;
//Debug::helloWorld(); //Fatal error: Class 'main\Debug' not found
util\Debug::helloWorld();
?>

<?php
namespace com\getinstance\util;
class Debug {
  static function helloWorld() {
    print "hello from Debug\n";
  }
}
namespace main;
use com\getinstance\util\Debug; // 直接使用到类
Debug::helloWorld();
?>

<?php
// no namespace
class Lister {
  public static function helloWorld() {
    print "hello from global\n";
  }
}
?>
<?php
namespace com\getinstance\util;
require_once 'global.php';
class Lister {
  public static function helloWorld() {
    print "hello from ".__NAMESPACE__."\n"; // __NAMESPACE__当前namespace
  }
}
Lister::helloWorld(); // access local
\Lister::helloWorld(); // access global
?>

<?php
namespace com\getinstance\util {
  class Debug {
    static function helloWorld() {
      print "hello from Debug\n";
    }
  }
}
namespace main {
  \com\getinstance\util\Debug::helloWorld();
}
?>

<?php
namespace { // 全局空间
  class Lister {
    public static function helloWorld() {
      print "hello from global\n";
    }
  }
}
namespace com\getinstance\util {
  class Lister {
    public static function helloWorld() {
      print "hello from ".__NAMESPACE__."\n";
    }
  }
  Lister::helloWorld(); // access local
  \Lister::helloWorld(); // access global
}
?>

<?php
class ShopProduct {
  function __construct() {
    print "ShopProduct constructor\n";
  }
}
?>
<?php
function __autoload( $classname ) { // 自动加载，根据类名加载类
  include_once( "$classname.php" );
}
$product = new ShopProduct( 'The Darkening', 'Harry', 'Hunter', 12.99 );
?>

<?php
class business_ShopProduct { // 这里的类命名就要遵循规则了
  function __construct() {
    print "business_ShopProduct constructor\n";
  }
}
?>
<?php
function __autoload( $classname ) {
  $path = str_replace('_', DIRECTORY_SEPARATOR, $classname ); // 智能化处理
  require_once( "$path.php" );
}
$x = new ShopProduct();
$y = new business_ShopProduct();
?>