课程进度 56% · 第13/22章第13/22章 · 标签 1/4
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常用扩展
PHP提供了丰富的内置扩展和第三方扩展。使用phpinfo()查看已安装的扩展，通过extension_loaded()检查扩展是否加载。
php
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// 检查扩展是否加载
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if (extension_loaded("mysqli")) {
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echo "MySQLi扩展已加载";
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}
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// 常用扩展示例
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// 1. PDO扩展
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try {
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$pdo = new PDO("mysql:host=localhost;dbname=test", "username", "password");
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} catch (PDOException $e) {
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echo "连接失败: " . $e->getMessage();
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}
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// 2. GD扩展（图像处理）
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if (extension_loaded("gd")) {
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$image = imagecreate(200, 200);
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$bg = imagecolorallocate($image, 255, 255, 255);
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$text_color = imagecolorallocate($image, 0, 0, 0);
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imagestring($image, 5, 50, 50, "Hello World", $text_color);
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imagepng($image, "hello.png");
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imagedestroy($image);
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}
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// 3. cURL扩展
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if (extension_loaded("curl")) {
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$ch = curl_init();
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curl_setopt($ch, CURLOPT_URL, "https://example.com");
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curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
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$response = curl_exec($ch);
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curl_close($ch);
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}
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扩展GDcURLPDOmysqli
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Composer基础
Composer是PHP的依赖管理工具。使用composer.json定义项目依赖，通过composer install安装依赖。
json
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{
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"name": "my/project",
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"description": "My PHP Project",
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"type": "project",
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"require": {
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"php": "^8.0",
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"monolog/monolog": "^2.0",
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"guzzlehttp/guzzle": "^7.0"
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},
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"require-dev": {
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"phpunit/phpunit": "^9.0",
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"symfony/var-dumper": "^5.0"
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},
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"autoload": {
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"psr-4": {
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"My\Project\": "src/"
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}
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}
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}
bash
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composer install // 安装依赖
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composer update // 更新依赖
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composer require package/name // 添加新依赖
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composer remove package/name // 移除依赖
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composer show // 查看已安装的包