喜欢面向对象的进来，看看我这个类，怎样写会更好，更容易让别人看懂，也更容易用于开发

[看小雪]

喜欢面向对象的进来，看看我这个类，怎样写会更好，更容易让别人看懂，也更容易用于开发。此类为数据库操作的类，只用于PDO且数据库为sqlite。当然，高手也可以改进下。

前景：以前我怕sqlite数据库出错，所以用了两个数据库，因此类里面有传数据库的地址。也算是我前期设计的一个失误吧。当然，能设计成静态调用更好。

<?php
/*
  此版本为utf-8(无BOM)版本，因为GBK编码在SQLITE3下处理不当会出现乱码。
  延续旧版本部分功能
*/

class   WEB {
	private  $conn ;
	private  $stmt ;
	public function __construct() {
		$this->CheckURL();
	}
	public function __destruct(){
		$this->conn=null;
		$this->stmt=null;
	}
	public function CheckURL() {
		$BadUrl = "'|and|create|delete|select|update|union|;|*|(|)";
		$url = empty($_SERVER["QUERY_STRING"])?"":$_SERVER["QUERY_STRING"];
		if(!empty($url)) {
			$arr = explode($BadUrl,"|");
			foreach($arr as $v) {
				if(stripos($url,$v)>0) {
					$this->CatchError("URL含有敏感字符");
					exit;
				}
			}
		}
	}

	public function CatchError($str='') {
		echo '<fieldset style="width:350px;padding: 3px;"><legend> 错误描述 </legend><br> 捕捉到错误，程序结束。 <p><font style="color:#ff0000;font-size:12px;">',$str, '</font></p><a href="http://'.$_SERVER['SERVER_NAME'].'" target="_blank" title="迷茫时代技术支持" style="margin: 3px 0px 2px 2px;color:#000;text-decoration: underline;">迷茫时代</a></fieldset>';
		exit();
	}
	//数据库操作区-------------------------------------
	public function ConnectDB($str) {
		if(!isset($str) || empty($str)) $this->CatchError("连接数据库字符串不能为空");
		if(!is_file($str)) $this->CatchError("没有此文件$str");
		$this->conn = new PDO('sqlite:'.$str) or $this->CatchError('连接数据库错误');

		return $this->conn;
	}


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

	public function query($str1,$db,$str2='',$str3='') {
		if(empty($str1)) $this->CatchError('查询数据库错误');
		if(!empty($str2)) {
			$str2 = $this->SQLParam($str2);
			$str1 = $str1.$str2;
		}
		if(!empty($str3)) $str1 = $str1.$str2.$str3;
		if(!$this->conn) $this->conn = $this->ConnectDB($db);

		$err	= $this->conn->errorInfo();
		$result = $this->conn->query($str1)  or  $this->CatchError("查询出错PDO<br>".$err[2]);
		$result->setFetchMode(PDO::FETCH_ASSOC);
		return $result;
	}
	public function querySingle($str1,$db,$str2=1) {
		if(empty($str1) or empty($db)) $this->CatchError('SQL is empty!');
		if(!$this->conn) $this->conn = $this->ConnectDB($db);
  		$result     = $this->conn->query($str1);
		if($str2==1) {
			$row      = $result->fetch(PDO::FETCH_ASSOC);
			return $row;
		}else{
			$row      = $result->fetch(PDO::FETCH_NUM);
			return $row[0];
		}
	}
	public function exec($str1,$db) {
		if(empty($str1)) $this->CatchError('SQL is empty!');
		if(!$this->conn) $this->conn = $this->ConnectDB($db);
		return $this->conn->exec($str1);
	}
	public function prepare($sql,$db) {
		if(empty($sql)) $this->CatchError('prepare need SQL!');
		if(!$this->conn) $this->conn = $this->ConnectDB($db);
		$this->stmt = $this->conn->prepare($sql);
	}
	public function bindValue($name,$value,$type) {
		if($type == 'TEXT') {
			$this->stmt->bindValue($name,$value,PDO::PARAM_STR);
		}else if($type == 'INT') {
			$this->stmt->bindValue($name,$value,PDO::PARAM_INT);
		}
	}
	public function execute() {
		$this->stmt->execute();
		$this->stmt->closeCursor();
	}
	public function errorInfo() {
		$arr = $this->stmt->errorInfo();
		$this->CatchError($arr[2]);
		$arr = NULL;
	}
	public function fetchColumn($int) {
		if(!is_numeric($int)) $this->CatchError('fetchColumn must be a number');
		$int = abs(intval($int));
		return  $this->stmt->fetchColumn($int) or $this->CatchError('the number is not in fetchColumn!');
	}
	public function SQLParam($str) {
		if(is_null($str) || empty($str) || (!isset($str))) return '';
		$str = str_replace("'","",$str);
		$str = str_replace("\\","",$str);
		$str = str_replace("\"","",$str);
		$str = str_replace("&","",$str);
		$str = str_replace("#","",$str);
		$str = str_replace(";","",$str);
		$str = str_replace("%","",$str);
		$str = str_replace("`","",$str);
		$str = preg_replace("/&(.)(acute|cedil|circ|ring|tilde|uml);/", "$1", $str);
		$str = preg_replace("/&(.)(uml);/", "$1e", $str);

		return $str;
	}
	//数据库操作区结束--------------------------------------------------

	function version(){
		return array(
			//'server' => $this->conn->getAttribute(PDO::ATTR_SERVER_INFO),
			'client version' => $this->conn->getAttribute(PDO::ATTR_CLIENT_VERSION),
			'driver name' => $this->conn->getAttribute(PDO::ATTR_DRIVER_NAME),
			'server version' => $this->conn->getAttribute(PDO::ATTR_SERVER_VERSION),
			//'connection' => $this->conn->getAttribute(PDO::ATTR_CONNECTION_STATUS)
		);
	}

	
}
?>