php單例模式數據庫類的簡單封裝

項目中常常要調用php鏈接數據庫（沒有使用PDO鏈接），使用設計模式中的單例模式作了簡單的封裝。另外能夠作爲客戶端app鏈接數據庫調用。

閒話少敘，具體以下：

 1 <?php
 2 
 3 class Db {
 4     static private $_instance;
 5     static private $_connectSource;
 6     private $_dbConfig = array(
 7         'host' => '127.0.0.1',
 8         'user' => 'root',
 9         'password' => '',
10         'database' => '',
11     );
12 
13     private function __construct() {
14     }
15 
16     static public function getInstance() {
17         if(!(self::$_instance instanceof self)) {
18             self::$_instance = new self();
19         }
20         return self::$_instance;
21     }
22 
23     public function connect() {
24         if(!self::$_connectSource) {
25             self::$_connectSource = @mysql_connect($this->_dbConfig['host'], $this->_dbConfig['user'], $this->_dbConfig['password']);    
26 
27             if(!self::$_connectSource) {
28                 throw new Exception('mysql connect error ' . mysql_error());
29                 //die('mysql connect error' . mysql_error());
30             }
31             
32             mysql_select_db($this->_dbConfig['database'], self::$_connectSource);
33             mysql_query("set names UTF8", self::$_connectSource);
34         }
35         return self::$_connectSource;
36     }
37 }