本文实例讲述了php实现带读写分离功能的MySQL类。分享给大家供大家参考，具体如下：

概述:

1. 根据sql语句判断是连接读库还是写库

2. 链式调用$this->where()->get()

3. 不同的主机对应不同的实例, 不再多次new

具体代码如下：

<?php class DBRWmysql { private static $Instance = null; private $links = array();//链接数组 private $link = null; //当前连接 public $dbType = 'read'; public $_host=''; //数据库所在主机名 public $_database = '';//当前数据库名 public $_tablename = '';//当前表的表名 public $_dt ='';//database.tablename public $isRelease = 0; //查询完成后是否释放 public $fields = '*'; public $arrWhere = []; public $order = ''; public $arrOrder = []; public $limit = ''; public $sql = ''; public $rs;//结果集 private function __construct($database='', $tablename='', $isRelease=0) { $this->_database = $database;//database name $this->_tablename = $tablename;//table name $this->_dt = "`{$this->_database}`.`{$this->_tablename}`"; $this->isRelease = $isRelease; } public static function getInstance($database='', $tablename='', $isRelease=0) { if (self::$Instance == null) { self::$Instance = new DBRWmysql($database, $tablename, $isRelease); } self::$Instance->_database = $database; self::$Instance->_tablename = $tablename; self::$Instance->_dt = "`{$database}`.`{$tablename}`"; self::$Instance->isRelease = $isRelease; return self::$Instance; } //如果主机没变,并且已经存在MYSQL连接,就不再创建新的连接 //如果主机改变,就再生成一个实例创建一个连接 //type == 'write'或'read' public function getLink($type) { $this->dbType = $$type; //随机选取一个数据库连接(区分读写) $dbConfig = DBConfig::$$type; $randKey = array_rand($dbConfig); $config = $dbConfig[$randKey]; //链接数据库 $host = $config['host']; $username = $config['username']; $password = $config['password']; if (empty($this->links[$host])) { $this->_host = $host; $this->links[$host] = new mysqli($host, $username, $password); if($this->links[$host]->connect_error) { $this->error($this->links[$host]->connect_error); } } //初始化链接 $this->link = $this->links[$host]; $this->link->query("set names utf8mb4;"); //支持emoji表情 $this->link->query("use {$this->_database};"); } public function getCurrentLinks() { return $this->links; } //析构函数 public function __destruct() { foreach ($this->links as $v) { $v->close(); } } //查询封装 public function query($sql) { $this->sql = $sql; if (strpos($sql, 'select') !== false) { $this->getLink('read');//读库 } else { $this->getLink('write');//写库 } $this->rs = $this->link->query($sql); ($this->rs === false) && $this->error('sql error: '.$sql.PHP_EOL.$this->link->error); //查询完成后释放链接, 并删除链接对象 if ($this->isRelease) { $this->link->close(); unset($this->links[$this->_host]); } return $this->rs; } //增 public function insert($arrData) { foreach ($arrData as $key=>$value) { $fields[] = $key; $values[] = "'".$value."'"; // $fields[] = '`'.$key.'`'; // $values[] = "'".$value."'"; } $strFields = implode(',', $fields); $strValues = implode(',', $values); $sql = "insert into {$this->_dt} ($strFields) values ($strValues)"; $this->query($sql); $insert_id = $this->link->insert_id; return $insert_id; } //增 public function replace($arrData) { foreach ($arrData as $key=>$value) { $fields[] = $key; $values[] = "'{$value}'"; } $strFields = implode(',', $fields); $strValues = implode(',', $values); $sql = "replace into {$this->_dt} ($strFields) values ($strValues)"; $this->query($sql); return $this->link->insert_id; } //增 //每次插入多条记录 //每条记录的字段相同,但是值不一样 public function insertm($arrFields, $arrData) { foreach ($arrFields as $v) { // $fields[] = "`{$v}`"; $fields[] = $v; } foreach ($arrData as $v) { $data[] = '('.implode(',', $v).')'; } $strFields = implode(',', $fields); $strData = implode(',', $data); $sql = "insert into {$this->_dt} ($strFields) values {$strData}"; $this->query($sql); return $this->link->insert_id; } //删 public function delete() { $where = $this->getWhere(); $limit = $this->getLimit(); $sql = " delete from {$this->_dt} {$where} {$limit}"; $this->query($sql); return $this->link->affected_rows; } //改 public function update($data) { $where = $this->getWhere(); $arrSql = array(); foreach ($data as $key=>$value) { $arrSql[] = "{$key}='{$value}'"; } $strSql = implode(',', $arrSql); $sql = "update {$this->_dt} set {$strSql} {$where} {$this->limit}"; $this->query($sql); return $this->link->affected_rows; } //获取总数 public function getCount() { $where = $this->getWhere(); $sql = " select count(1) as n from {$this->_dt} {$where} "; $resault = $this->query($sql); ($resault===false) && $this->error('getCount error: '.$sql); $arrRs = $this->rsToArray($resault); $num = array_shift($arrRs); return $num['n']; } //将结果集转换成数组返回 //如果field不为空，则返回的数组以$field为键重新索引 public function rsToArray($field = '') { $arrRs = $this->rs->fetch_all(MYSQLI_ASSOC); //该函数只能用于php的mysqlnd驱动 $this->rs->free();//释放结果集 if ($field) { $arrResult = []; foreach ($arrRs as $v) { $arrResult[$v[$field]] = $v; } return $arrResult; } return $arrRs; } //给字段名加上反引号 public function qw($strFields) { $strFields = preg_replace('#s+#', ' ', $strFields); $arrNewFields = explode(' ', $strFields ); $arrNewFields = array_filter($arrNewFields); foreach ($arrNewFields as $k => $v) { $arrNewFields[$k]= '`'.$v.'`'; } return implode(',', $arrNewFields); } //处理入库数据,将字符串格式的数据转换为...格式(未实现) public function getInsertData($strData) { // $bmap = "jingdu,$jingdu weidu,$weidu content,$content"; } //select in //arrData 整数数组，最好是整数 public function select_in($key, $arrData, $fields='') { $fields = $fields ? $fields : '*'; sort($arrData); $len = count($arrData); $cur = 0; $pre = $arrData[0]; $new = array('0' => array($arrData[0])); for ($i = 1; $i < $len; $i++) { if (($arrData[$i] - $pre) == 1 ) { $new[$cur][] = $arrData[$i]; } else { $cur = $i; $new[$cur][] = $arrData[$i]; } $pre = $arrData[$i]; } $arrSql = array(); foreach ($new as $v) { $len = count($v) - 1; if ($len) { $s = $v[0]; $e = end($v); $sql = "(select $fields from {$this->_dt} where $key between $s and $e)"; } else { $s = $v[0]; $sql = "(select $fields from {$this->_dt} where $key = $s)"; } $arrSql[] = $sql; } $strUnion = implode(' UNION ALL ', $arrSql); $res = $this->query($strUnion); return $this->rstoarray($res); } //where in public function setWhereIn($key, $arrData) { if (empty($arrData)) { $str = "(`{$key}` in ('0'))"; $this->addWhere($str); return $str; } foreach ($arrData as &$v) { $v = "'{$v}'"; } $str = implode(',', $arrData); $str = "(`{$key}` in ( {$str} ))"; $this->addWhere($str); return $this; } //where in public function setWhere($arrData) { if (empty($arrData)) { return ''; } foreach ($arrData as $k => $v) { $str = "(`{$k}` = '{$v}')"; $this->addWhere($str); } return $this; } //between and public function setWhereBetween($key, $min, $max) { $str = "(`{$key}` between '{$min}' and '{$max}')"; $this->addWhere($str); return $this; } //where a>b public function setWhereBT($key, $value) { $str = "(`{$key}` > '{$value}')"; $this->addWhere($str); return $this; } //where a<b public function setWhereLT($key, $value) { $str = "(`{$key}` < '{$value}')"; $this->addWhere($str); return $this; } //组装where条件 public function addWhere($where) { $this->arrWhere[] = $where; } //获取最终查询用的where条件 public function getWhere() { if (empty($this->arrWhere)) { return 'where 1'; } else { return 'where '.implode(' and ', $this->arrWhere); } } //以逗号隔开 public function setFields($fields) { $this->fields = $fields; return $this; } // order by a desc public function setOrder($order) { $this->arrOrder[] = $order; return $this; } //获取order语句 public function getOrder() { if (empty($this->arrOrder)) { return ''; } else { $str = implode(',', $this->arrOrder); $this->order = "order by {$str}"; } return $this->order; } //e.g. '0, 10' //用limit的时候可以加where条件优化：select ... where id > 1234 limit 0, 10 public function setLimit($limit) { $this->limit = 'limit '.$limit; return $this; } //直接查询sql语句, 返回数组格式 public function arrQuery($sql, $field='') { $this->query($sql); $this->clearQuery(); ($this->rs===false) && $this->error('select error: '.$sql); return $this->rsToArray($field); } //如果 $field 不为空, 则返回的结果以该字段的值为索引 //暂不支持join public function get($field='') { $where = $this->getWhere(); $order = $this->getOrder(); $sql = " select {$this->fields} from {$this->_dt} {$where} {$order} {$this->limit} "; return $this->arrQuery($sql, $field); } //获取一条记录 public function getOne() { $this->setLimit(1); $rs = $this->get(); return !empty($rs) ? $rs[0] : []; } //获取一条记录的某一个字段的值 public function getOneField($field) { $this->setFields($field); $rs = $this->getOne(); return !empty($rs[$field]) ? $rs[$field] : ''; } //获取数据集中所有某个字段的值 public function getFields($field) { $this->setFields($field); $rs = $this->get(); $result = []; foreach ($rs as $v) { $result[] = $v[$field]; } unset($rs); return $result; } //清除查询条件 //防止干扰下次查询 public function clearQuery() { $this->fields = '*'; $this->arrWhere = []; $this->order = ''; $this->arrOrder = []; $this->limit = ''; } //断开数据库连接 public function close() { $this->link->close(); } //事务 //自动提交开关 public function autocommit($bool) { $this->link->autocommit($bool); } //事务完成提交 public function commit() { $this->link->commit(); } //回滚 public function rollback() { $this->link->rollback(); } //输出错误sql语句 public function error($sql) { //if (IS_TEST) {} exit($sql); } }

希望本文所述对大家PHP程序设计有所帮助。