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();
?>