sql防注入代码 php

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

try {
    // 创建PDO连接
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    // 用户输入
    $userInput = $_POST['username'];

    // 使用预处理语句防止SQL注入
    $stmt = $conn->prepare("SELECT * FROM users WHERE username = :username");
    $stmt->bindParam(':username', $userInput);
    $stmt->execute();

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

    // 输出结果
    foreach ($result as $row) {
        echo "ID: " . $row['id'] . " - Username: " . $row['username'] . "<br>";
    }
} catch (PDOException $e) {
    echo "Error: " . $e->getMessage();
}

$conn = null;
?>