转自：http://hudeyong926.iteye.com/blog/902785

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<?php 
/** 
* Mysqli类 
* 
* @author 废墟 
* @version v1.0 2009-08-18 
* @link http://anerg.cn/ 
*/ 
class db_mysqli { 
	protected $mysqli; 
	protected $sql; 
	protected $rs; 
	protected $query_num    = 0; 
	protected $fetch_mode    = MYSQLI_ASSOC; 
	protected $cache_dir    = './cache/'; 
	protected $cache_time    = 1800; 

	public function  __construct($dbhost, $dbuser, $dbpass, $dbname) { 
		$this->mysqli    = new mysqli($dbhost, $dbuser, $dbpass, $dbname); 
		if(mysqli_connect_errno()) { 
			$this->mysqli    = false; 
			echo '<h2>'.mysqli_connect_error().'</h2>'; 
			die(); 
		} else { 
			$this->mysqli->set_charset("utf8"); 
		} 
	} 

	public function  __destruct() { 
		$this->free(); 
		$this->close(); 
	} 

	protected function free() { 
		@$this->rs->free(); 
	} 

	protected function close() { 
		$this->mysqli->close(); 
	} 

	protected function fetch() { 
		return $this->rs->fetch_array($this->fetch_mode); 
	} 

	protected function getQuerySql($sql, $limit = null) { 
		if (@preg_match("/[0-9]+(,[ ]?[0-9]+)?/is", $limit) && !preg_match("/ LIMIT [0-9]+(,[ ]?[0-9]+)?$/is", $sql)) { 
			$sql .= " LIMIT " . $limit; 
		} 
		return $sql; 
	} 

	protected function get_cache($sql,$method) { 
		include_once './cache.php';//若框架中使用__autoload()，这里可以不用加载文件 
		$cache    = new cache($this->cache_dir,$this->cache_time); 
		$cache_file    = md5($sql.$method); 
		$res    = $cache->get_cache($cache_file); 
		if(!$res) { 
			$res    = $this->$method($sql); 
			$cache->set_cache($cache_file, $res); 
		} 
		return $res; 
	} 

	public function query_num() { 
		return $this->query_num; 
	} 

	public function set_cache_dir($cache_dir) { 
		$this->cache_dir    = $cache_dir; 
	} 

	public function set_cache_time($cache_time) { 
		$this->cache_time    = $cache_time; 
	} 

	public function query($sql, $limit = null) { 
		$sql    = $this->getQuerySql($sql, $limit); 
		$this->sql    = $sql; 
		$this->rs    = $this->mysqli->query($sql); 
		if (!$this->rs) { 
			echo "<h2>".$this->mysqli->error."</h2>"; 
			die(); 
		} else { 
		$this->query_num++; 
			return $this->rs; 
		} 
	} 

	public function getOne($sql) { 
		$this->query($sql, 1); 
		$this->fetch_mode    = MYSQLI_NUM; 
		$row = $this->fetch(); 
		$this->free(); 
		return $row[0]; 
	} 

	public function get_one($sql) { 
		return $this->getOne($sql); 
	} 

	public function cache_one($sql) { 
		$sql    = $this->getQuerySql($sql, 1); 
		return $this->get_cache($sql, 'getOne'); 
	} 

	public function getRow($sql, $fetch_mode = MYSQLI_ASSOC) { 
		$this->query($sql, 1); 
		$this->fetch_mode    = $fetch_mode; 
		$row = $this->fetch(); 
		$this->free(); 
		return $row; 
	} 

	public function get_row($sql, $fetch_mode = MYSQLI_ASSOC) { 
		return $this->getRow($sql);
	} 

	public function cache_row($sql) { 
		$sql    = $this->getQuerySql($sql, 1); 
		return $this->get_cache($sql, 'getRow'); 
	} 

	public function getAll($sql, $limit = null, $fetch_mode = MYSQLI_ASSOC) { 
		$this->query($sql, $limit); 
		$all_rows = array(); 
		$this->fetch_mode    = $fetch_mode; 
		while($rows = $this->fetch()) { 
			$all_rows[] = $rows; 
		} 
		$this->free(); 
		return $all_rows; 
	} 
	public function get_all($sql, $limit = null, $fetch_mode = MYSQLI_ASSOC) { 
		return $this->getAll($sql); 
	} 
	
	public function cache_all($sql, $limit = null) { 
		$sql    = $this->getQuerySql($sql, $limit); 
		return $this->get_cache($sql, 'getAll'); 
	} 

	public function insert_id() { 
		return $this->mysqli->insert_id(); 
	} 

	public function escape($str) { 
		if(is_array($str)) { 
			foreach($str as $key=>$val) { 
				$str[$key] = $this->escape($val); 
			} 
		} else { 
			$str = addslashes(trim($str)); 
		} 
		return $str; 
	} 
}