php mysql登录密码判断

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

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 预处理语句防止SQL注入
$stmt = $conn->prepare("SELECT password FROM users WHERE username = ?");
$stmt->bind_param("s", $input_username);

$input_username = $_POST['username'];
$stmt->execute();

$result = $stmt->get_result();
$row = $result->fetch_assoc();

if ($row) {
    $hashed_password = $row['password'];
    if (password_verify($_POST['password'], $hashed_password)) {
        echo "登录成功";
    } else {
        echo "密码错误";
    }
} else {
    echo "用户名不存在";
}

$stmt->close();
$conn->close();
?>