PHP生成excel(2)

<?php
class Db {

    private static $_instance;
    private $conn = null;
    private function __construct() {
        require "./dbconfig.php";
        $this->conn = mysql_connect($config[‘host‘],$config[‘username‘],$config[‘password‘]) or die(mysql_error);
        mysql_select_db($config[‘database‘],$this->conn) or die(mysql_error());
        mysql_query(‘set names ‘.$config[‘charset‘]);
    }
    
    //查询结果集
    public function getResult($sql) {
        $resource = mysql_query($sql,$this->conn) or die(mysql_error());
        $res = array();
        while($row = mysql_fetch_assoc($resource)) {
            $res[] = $row;
        }
        return $res;
    }

    //单例模式
    public static function getInstance() {
        if (!self::$_instance instanceof self) {
            self::$_instance = new self();
        }
        return self::$_instance;
    }

    private function __clone() {
        trigger_error(‘Clone is not allow!‘,E_USER_ERROR);
    }
}

<?php
header("Content-Type:text/html;charset=utf-8");
require "./db.php";
require "./PHPExcel/PHPExcel.php";

//连接数据库
$db = Db::getInstance();

//实例化excel类
$objPHPExcel = new PHPExcel();

//创建sheet
for ($i=1; $i<=3; $i++) {
    if ($i > 1) { //默认已经有一个sheet，从第二个开始创建
        $objPHPExcel->createSheet();
    }
    $objPHPExcel->setActiveSheetIndex($i-1);
    //获得当前活动sheet的操作对象
    $objSheet = $objPHPExcel->getActiveSheet();

    //设置sheet标题
    $objSheet->setTitle($i.‘年级‘);

    //从数据库查询数据
    $Db = Db::getInstance();
    
    //查询每个年级的活动数据
    $data = $Db->getResult("select * from user where grade = ".$i);

    $objSheet->setCellValue("A1","姓名")->setCellValue("B1","分数")->setCellValue("C1","班级");

    //添加数据
    $j = 2;
    foreach ($data as $value) {
        $objSheet->setCellValue("A".$j,$value[‘username‘])->setCellValue("B".$j,$value[‘score‘])->setCellValue("C".$j,$value[‘grade‘]);
        $j++;
    }
}

//按照指定格式生成excel文件
$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, ‘Excel2007‘);//生成excel 2007
$objWriter->save(‘class.xlsx‘);

//如果需要输出到浏览器，请打开以下注释和注释掉save行
//输出到浏览器
/*browser_export(‘Excel7‘,‘export.xlsx‘);
$objWriter->save(‘php://output‘);
function browser_export($type,$exportName) {
    //输出到浏览器
    if ($type == ‘Excel5‘) {
        header(‘Content-Type: application/vnd.ms-excel‘);//excel03
    } else {
        header(‘Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet‘);//excel07
    }
    header(‘Content-Disposition: attachment;filename="‘.$exportName.‘"‘);//文件名称
    header(‘Cache-Control: max-age=0‘);//禁止浏览器缓存
}*/