<?php class Mysql {  private $host;  private $user;  private $pwd;  private $dbName;  private $charset;  private $conn = null;  public function __construct() {   $this->host = 'localhost';   $this->user = 'root';   $this->pwd = 'root';   $this->dbName = 'test';   $this->connect($this->host,$this->user,$this->pwd);   $this->switchDb($this->dbName);   $this->setChar($this->charset);  }  //负责链接  private function connect($h,$u,$p) {   $conn = mysql_connect($h,$u,$p);   $this->conn = $conn;  }  //负责切换数据库  public function switchDb($db) {   $sql = 'use' . $db;   $this->query($sql);  }  //负责设置字符集  public function setChar($char) {   $sql = 'set names' . $char;   $this->query($sql);  }  //负责发送sql查询  public function query($sql) {   return mysql_query($sql,$this->conn);  }  //负责获取多行多列的select结果  public function getAll($sql) {   $list = array();   $rs = $this->query($sql);   if (!$rs) {    return false;   }   while ($row = mysql_fetch_assoc($rs)) {    $list[] = $row;   }   return $list;  }  public function getRow($sql) {   $rs = $this->query($sql);   if(!$rs) {    return false;   }   return mysql_fetch_assoc($rs);  }  public function getOne($sql) {   $rs = $this->query($sql);   if (!$rs) {    return false;   }   return mysql_fetch_assoc($rs);   return $row[0];  }  public function close() {   mysql_close($this->conn);  } } echo '<pre>'; $mysql = new Mysql(); print_r($mysql); $sql = "insert into stu values (4,'wangwu','99998')"; if($mysql->query($sql)){  echo "query成功"; }else {  echo "失败"; } echo "<br />"; $sql = "select * from stu"; $arr = $mysql->getAll($sql); print_r($arr); ?>