封装mysqli

<?php
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'] : 'wan';
 $this->charset=isset($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($arr)
 {
 echo "<pre>";
 print_r($arr);
 echo "</pre>";
 }

 public function v($arr)
 {
 echo "<pre>";
 var_dump($arr);
 echo "</pre>";
 }

 //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：

<?php
//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);

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