登录php中的mysql

<?php
try {
    // 数据库连接配置
    $dsn = 'mysql:host=localhost;dbname=testdb';
    $username = 'your_username';
    $password = 'your_password';

    // 创建PDO实例
    $pdo = new PDO($dsn, $username, $password);

    // 设置错误处理模式为异常
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    // 预处理SQL语句
    $stmt = $pdo->prepare('SELECT * FROM users WHERE username = :username AND password = :password');
    $stmt->bindParam(':username', $username);
    $stmt->bindParam(':password', $password);

    // 执行查询
    $stmt->execute();

    // 获取结果集
    $result = $stmt->fetch(PDO::FETCH_ASSOC);

    if ($result) {
        echo '登录成功！';
    } else {
        echo '用户名或密码错误！';
    }
} catch (PDOException $e) {
    echo '数据库连接失败：' . $e->getMessage();
}
?>