php封装的mysqli类完整实例

header('content-type:text/html;charset=utf-8');
/*
掌握满足单例模式的必要条件
(1)私有的构造方法-为了防止在类外使用new关键字实例化对象
(2)私有的成员属性-为了防止在类外引入这个存放对象的属性
(3)私有的克隆方法-为了防止在类外通过clone成生另一个对象
(4)公有的静态方法-为了让用户进行实例化对象的操作
*/
class ConnectMysqli{
    //私有的属性
    private static $dbcon=false;
    private $host;
    private $port;
    private $user;
    private $pass;
    private $db;
    private $charset;
    private $link;
    //私有的构造方法
    private function __construct($config=array()){
        $this->host = $config['host'] ? $config['host'] : 'localhost';
        $this->port = $config['port'] ? $config['port'] : '3306';
        $this->user = $config['user'] ? $config['user'] : 'root';
        $this->pass = $config['pass'] ? $config['pass'] : 'root';
        $this->db = $config['db'] ? $config['db'] : 'small2';
        $this->charset=isset($arr['charset']) ? $arr['charset'] : 'utf8';
        //连接数据库
        $this->db_connect();
        //选择数据库
        $this->db_usedb();
        //设置字符集
        $this->db_charset();
    }
    //连接数据库
    private function db_connect(){
        $this->link=mysqli_connect($this->host.':'.$this->port,$this->user,$this->pass);
        if(!$this->link){
            echo "数据库连接失败
";
            echo "错误编码".mysqli_errno($this->link)."
";
            echo "错误信息".mysqli_error($this->link)."
";
            exit;
        }
    }
    //设置字符集
    private function db_charset(){
        mysqli_query($this->link,"set names {$this->charset}");
    }
    //选择数据库
    private function db_usedb(){
        mysqli_query($this->link,"use {$this->db}");
    }
    //私有的克隆
    private function __clone(){
        die('clone is not allowed');
    }
    //公用的静态方法
    public static function getIntance(){
        if(self::$dbcon==false){
            self::$dbcon=new self;
        }
        return self::$dbcon;
    }
    //执行sql语句的方法
    public function query($sql){
        $res=mysqli_query($this->link,$sql);
        if(!$res){
            echo "sql语句执行失败
";
            echo "错误编码是".mysqli_errno($this->link)."
";
            echo "错误信息是".mysqli_error($this->link)."
";
        }
        return $res;
    }
    //打印数据
    public function p($arr){
        echo "

"; print_r($arr); echo "

"; } public function v($arr){ echo "

";
        var_dump($arr);
        echo "

"; } //获得最后一条记录id public function getInsertid(){ return mysqli_insert_id($this->link); } /** * 查询某个字段 * @param * @return string or int */ public function getOne($sql){ $query=$this->query($sql); return mysqli_free_result($query); } //获取一行记录,return array 一维数组 public function getRow($sql,$type="assoc"){ $query=$this->query($sql); if(!in_array($type,array("assoc",'array',"row"))){ die("mysqli_query error"); } $funcname="mysqli_fetch_".$type; return $funcname($query); } //获取一条记录,前置条件通过资源获取一条记录 public function getFormSource($query,$type="assoc"){ if(!in_array($type,array("assoc","array","row"))) { die("mysqli_query error"); } $funcname="mysqli_fetch_".$type; return $funcname($query); } //获取多条数据，二维数组 public function getAll($sql){ $query=$this->query($sql); $list=array(); while ($r=$this->getFormSource($query)) { $list[]=$r; } return $list; } /** * 定义添加数据的方法 * @param string $table 表名 * @param string orarray $data [数据] * @return int 最新添加的id */ public function insert($table,$data){ //遍历数组，得到每一个字段和字段的值 $key_str=''; $v_str=''; foreach($data as $key=>$v){ if(empty($v)){ die("error"); } //$key的值是每一个字段s一个字段所对应的值 $key_str.=$key.','; $v_str.="'$v',"; } $key_str=trim($key_str,','); $v_str=trim($v_str,','); //判断数据是否为空 $sql="insert into $table ($key_str) values ($v_str)"; $this->query($sql); //返回上一次增加操做产生ID值 return $this->getInsertid(); } /* * 删除一条数据方法 * @param1 $table, $where=array('id'=>'1') 表名 条件 * @return 受影响的行数 */ public function deleteOne($table, $where){ if(is_array($where)){ foreach ($where as $key => $val) { $condition = $key.'='.$val; } } else { $condition = $where; } $sql = "delete from $table where $condition"; $this->query($sql); //返回受影响的行数 return mysqli_affected_rows($this->link); } /* * 删除多条数据方法 * @param1 $table, $where 表名 条件 * @return 受影响的行数 */ public function deleteAll($table, $where){ if(is_array($where)){ foreach ($where as $key => $val) { if(is_array($val)){ $condition = $key.' in ('.implode(',', $val) .')'; } else { $condition = $key. '=' .$val; } } } else { $condition = $where; } $sql = "delete from $table where $condition"; $this->query($sql); //返回受影响的行数 return mysqli_affected_rows($this->link); } /** * [修改操作description] * @param [type] $table [表名] * @param [type] $data [数据] * @param [type] $where [条件] * @return [type] */ public function update($table,$data,$where){ //遍历数组，得到每一个字段和字段的值 $str=''; foreach($data as $key=>$v){ $str.="$key='$v',"; } $str=rtrim($str,','); //修改SQL语句 $sql="update $table set $str where $where"; $this->query($sql); //返回受影响的行数 return mysqli_affected_rows($this->link); } } ?>

 

用法测试：

 

//mysqli测试
$db=ConnectMysqli::getIntance();
//var_dump($db);
/*$sql="select * from acticle";
$list=$db->getAll($sql);
$db->p($list);*/
/*$sql="select * from acticle where acticle_id=95";
$list=$db->getRow($sql);
$db->p($list);
*/
/*$sql="select title from acticle";
$list=$db->getOne($sql);
$db->p($list);不行*/
//$list=$db->insert("users",$_POST);
//$del=$db->deleteOne("users","id=29");
//$del=$db->deleteAll("users","id in(27,28)");
//$up=$db->update("users",$_POST,"id=27");
//print_R($list);