如何从PHP中的外部文件创建对象

Question

我在一个类中有一个mySQL对象，它位于外部文件中（以便从其他几个文件访问它）。我怎样才能让我的Singleton对象从我的文件dbconnection.php：

<?php 
class DBConnection { 

    private static $instance; 

    private function __construct() { 
    $user="root"; 
    $password=""; 
    $database="klb"; 
    mysql_connect("localhost",$user,$password); 
    @mysql_select_db($database) or die("Unable to select database"); 
} 

    public function __destruct() { 
     mysql_close(); 
} 

    public static function getInstance() { 

    if(!self::$instance) { 
     self::$instance = new self(); 
    } 

    return self::$instance; 
    } 

    public function getNaviForCategory($category) { 
    $query="SELECT * FROM projects WHERE category=\"$category\""; 
    $result=mysql_query($query); 
    $num=mysql_numrows($result); 
    while ($row = mysql_fetch_object($result)) { 
     $title=$row->title; 
     $id=$row->id; 
     echo "<div class=\"sublink\" data-subsite=\"$id\" data-category=\"$category\" data-title=\"$title\" ><a href=\"#\">$title<br />"; 
    } 
    } 

public function getInfosForProject($id) { 
    $query="SELECT * FROM projects WHERE id=\"$id\""; 
    $result=mysql_query($query); 
    $num=mysql_numrows($result); 

    while ($row = mysql_fetch_object($result)) { 
     $infos=$row->info; 
     echo $infos; 
    } 
    } 

    private function createTableProjects(){ 
     $query="CREATE TABLE projects (id int(6) NOT NULL auto_increment,category varchar(30) NOT NULL,title varchar(30) NOT NULL, 
     info varchar(200) NOT NULL,text varchar(8000) NOT NULL,PRIMARY KEY (id),UNIQUE id (id))"; 
     mysql_query($query); 
    } 
} 

?> 

Answer 1

您需要include()或require()文件第一：

require('dbconnection.php'); 

然后，你可以这样做：

$db = DBConnection::getInstance();