The example in this article describes the mysqli class encapsulated in php. Share it with everyone for your reference, as follows:

Class:

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);
/*
掌握滿足單例模式的必要條件
(1)私有的構(gòu)造方法-為了防止在類外使用new關(guān)鍵字實(shí)例化對象
(2)私有的成員屬性-為了防止在類外引入這個(gè)存放對象的屬性
(3)私有的克隆方法-為了防止在類外通過clone成生另一個(gè)對象
(4)公有的靜態(tài)方法-為了讓用戶進(jìn)行實(shí)例化對象的操作
*/
class ConnectMysqli{
  //私有的屬性
  private static $dbcon=false;
  private $host;
  private $port;
  private $user;
  private $pass;
  private $db;
  private $charset;
  private $link;
  //私有的構(gòu)造方法
  private function __construct($config=array()){
    $this->host = $config[&#39;host&#39;] ? $config[&#39;host&#39;] : &#39;localhost&#39;;
    $this->port = $config[&#39;port&#39;] ? $config[&#39;port&#39;] : &#39;3306&#39;;
    $this->user = $config[&#39;user&#39;] ? $config[&#39;user&#39;] : &#39;root&#39;;
    $this->pass = $config[&#39;pass&#39;] ? $config[&#39;pass&#39;] : &#39;root&#39;;
    $this->db = $config[&#39;db&#39;] ? $config[&#39;db&#39;] : &#39;small2&#39;;
    $this->charset=isset($arr[&#39;charset&#39;]) ? $arr[&#39;charset&#39;] : &#39;utf8&#39;;
    //連接數(shù)據(jù)庫
    $this->db_connect();
    //選擇數(shù)據(jù)庫
    $this->db_usedb();
    //設(shè)置字符集
    $this->db_charset();
   }
   //連接數(shù)據(jù)庫
   private function db_connect(){
    $this->link=mysqli_connect($this->host.&#39;:&#39;.$this->port,$this->user,$this->pass);
    if(!$this->link){
      echo "數(shù)據(jù)庫連接失敗<br>";
      echo "錯(cuò)誤編碼".mysqli_errno($this->link)."<br>";
      echo "錯(cuò)誤信息".mysqli_error($this->link)."<br>";
      exit;
    }
   }
   //設(shè)置字符集
    private function db_charset(){
     mysqli_query($this->link,"set names {$this->charset}");
    }
    //選擇數(shù)據(jù)庫
   private function db_usedb(){
     mysqli_query($this->link,"use {$this->db}");
   }
   //私有的克隆
   private function __clone(){
     die(&#39;clone is not allowed&#39;);
   }
   //公用的靜態(tài)方法
   public static function getIntance(){
     if(self::$dbcon==false){
      self::$dbcon=new self;
     }
     return self::$dbcon;
   }
   //執(zhí)行sql語句的方法
    public function query($sql){
     $res=mysqli_query($this->link,$sql);
     if(!$res){
      echo "sql語句執(zhí)行失敗<br>";
      echo "錯(cuò)誤編碼是".mysqli_errno($this->link)."<br>";
      echo "錯(cuò)誤信息是".mysqli_error($this->link)."<br>";
     }
     return $res;
   }
   //打印數(shù)據(jù)
    public function p($arr){
      echo "<pre class="brush:php;toolbar:false">";
      print_r($arr);
      echo "

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

";
      var_dump($arr);
      echo "

"; } //獲得最后一條記錄id public function getInsertid(){ return mysqli_insert_id($this->link); } /** * 查詢某個(gè)字段 * @param * @return string or int */ public function getOne($sql){ $query=$this->query($sql); return mysqli_free_result($query); } //獲取一行記錄,return array 一維數(shù)組 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); } //獲取一條記錄,前置條件通過資源獲取一條記錄 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); } //獲取多條數(shù)據(jù)，二維數(shù)組 public function getAll($sql){ $query=$this->query($sql); $list=array(); while ($r=$this->getFormSource($query)) { $list[]=$r; } return $list; } /** * 定義添加數(shù)據(jù)的方法 * @param string $table 表名 * @param string orarray $data [數(shù)據(jù)] * @return int 最新添加的id */ public function insert($table,$data){ //遍歷數(shù)組，得到每一個(gè)字段和字段的值 $key_str=''; $v_str=''; foreach($data as $key=>$v){ if(empty($v)){ die("error"); } //$key的值是每一個(gè)字段s一個(gè)字段所對應(yīng)的值 $key_str.=$key.','; $v_str.="'$v',"; } $key_str=trim($key_str,','); $v_str=trim($v_str,','); //判斷數(shù)據(jù)是否為空 $sql="insert into $table ($key_str) values ($v_str)"; $this->query($sql); //返回上一次增加操做產(chǎn)生ID值 return $this->getInsertid(); } /* * 刪除一條數(shù)據(jù)方法 * @param1 $table, $where=array('id'=>'1') 表名 條件 * @return 受影響的行數(shù) */ public function deleteOne($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); //返回受影響的行數(shù) return mysqli_affected_rows($this->link); } /* * 刪除多條數(shù)據(jù)方法 * @param1 $table, $where 表名 條件 * @return 受影響的行數(shù) */ public function deleteAll($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); //返回受影響的行數(shù) return mysqli_affected_rows($this->link); } /** * [修改操作description] * @param [type] $table [表名] * @param [type] $data [數(shù)據(jù)] * @param [type] $where [條件] * @return [type] */ public function update($table,$data,$where){ //遍歷數(shù)組，得到每一個(gè)字段和字段的值 $str=''; foreach($data as $key=>$v){ $str.="$key='$v',"; } $str=rtrim($str,','); //修改SQL語句 $sql="update $table set $str where $where"; $this->query($sql); //返回受影響的行數(shù) return mysqli_affected_rows($this->link); } } ?>

Usage test:

//mysqli測試
$db=ConnectMysqli::getIntance();
//var_dump($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);

For more articles related to complete examples of mysqli classes encapsulated in PHP, please pay attention to the PHP Chinese website!