在所有的php office库(http://www.21doc.net/php/awesomephp#Office)，以前用得最多的版本是PHPOffice/PHPExcel（https://github.com/PHPOffice/PHPExcel），不过该库最后更新的版本为2015发布的1.8.1版本，已经终止维护，官方也不建议用户继续使用。

官方不维护PHPExcel后，新起一个项目叫PhpSpreadsheet（https://github.com/PHPOffice/PhpSpreadsheet）。新项目使用了大量的php新特性，比如命名空间，PSR标准，性能也比PHPExcel高了不少。

在使用时，由于PhpSpreadsheet是在原PHPExcel基础上开发的，PhpSpreadsheet接口api操作上也和旧的PHPExcel相似，而且支持更多的格式。

整合到yii2框架

下载phpspreadsheet，当前最新版本1.5.0
方式一，composer下载

composer require phpoffice/phpspreadsheet

方式二，对于部分不能用composer顺利下载的用户，可以手工下载源码
PhpSpreadsheet
下载地址：https://github.com/PHPOffice/PhpSpreadsheet/releases

simple-cache (注意：PhpSpreadsheet的依赖库，必须也下载)
下载地址：https://github.com/php-fig/simple-cache/releases

把下载的文件放置在下边目录，如下图：

phpspreadsheet类库命名方式符合 PSR-4 标准，使用 Yii 官方的自动加载器来自动加载这些类。 你只需给他们的每个根命名空间声明一下根路径别名。 
main.php

<?php
return ['aliases' => ['@bower' => '@vendor/bower-asset','@npm'   => '@vendor/npm-asset','@Psr/SimpleCache' => '@vendor/psr/simple-cache/src','@PhpOffice' => '@vendor/phpoffice/phpspreadsheet/src',],'vendorPath' => dirname(dirname(__DIR__)) . '/vendor',......
];

PhpSpreadsheet自带很多例子代码，参考phpoffice\phpspreadsheet\samples\Basic\01_Simple_download_xlsx.php实现一个http导出excel功能。

yii2中导出excel实现：

ExcelController.php

<?php
namespace frontend\controllers;use Yii;
use yii\web\Controller;
use PhpOffice\PhpSpreadsheet\IOFactory;
use PhpOffice\PhpSpreadsheet\Spreadsheet;class ExcelController extends Controller
{public function actionIndex(){// Create new Spreadsheet object$spreadsheet = new Spreadsheet();// Set document properties$spreadsheet->getProperties()->setCreator('Maarten Balliauw')->setLastModifiedBy('Maarten Balliauw')->setTitle('Office 2007 XLSX Test Document')->setSubject('Office 2007 XLSX Test Document')->setDescription('Test document for Office 2007 XLSX, generated using PHP classes.')->setKeywords('office 2007 openxml php')->setCategory('Test result file');// Add some data$spreadsheet->setActiveSheetIndex(0)->setCellValue('A1', 'Hello')->setCellValue('B2', 'world!')->setCellValue('C1', 'Hello')->setCellValue('D2', 'world!');// Miscellaneous glyphs, UTF-8$spreadsheet->setActiveSheetIndex(0)->setCellValue('A4', 'Miscellaneous glyphs')->setCellValue('A5', 'éàèùâêîôûëïüÿäöüç');// Rename worksheet$spreadsheet->getActiveSheet()->setTitle('Simple');// Set active sheet index to the first sheet, so Excel opens this as the first sheet$spreadsheet->setActiveSheetIndex(0);// Redirect output to a client’s web browser (Xlsx)header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');header('Content-Disposition: attachment;filename="01simple.xlsx"');header('Cache-Control: max-age=0');// If you're serving to IE 9, then the following may be neededheader('Cache-Control: max-age=1');// If you're serving to IE over SSL, then the following may be neededheader('Expires: Mon, 26 Jul 1997 05:00:00 GMT'); // Date in the pastheader('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT'); // always modifiedheader('Cache-Control: cache, must-revalidate'); // HTTP/1.1header('Pragma: public'); // HTTP/1.0$writer = IOFactory::createWriter($spreadsheet, 'Xlsx');$writer->save('php://output');exit;}
}

访问http://localhost/yii2/frontend/web/index.php?r=excel/index，生成的文件内容如下：