php mysql用户注册登录

<?php
$servername = "localhost";
$username = "root";
$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);
}

// 注册逻辑
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $username = $_POST['username'];
    $password = $_POST['password'];
    $hashed_password = password_hash($password, PASSWORD_DEFAULT);

    $sql = "INSERT INTO users (username, password) VALUES ('$username', '$hashed_password')";

    if ($conn->query($sql) === TRUE) {
        echo "注册成功";
    } else {
        echo "错误: " . $sql . "<br>" . $conn->error;
    }
}

$conn->close();
?>

<?php
$servername = "localhost";
$username = "root";
$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);
}

// 登录逻辑
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $username = $_POST['username'];
    $password = $_POST['password'];

    $sql = "SELECT * FROM users WHERE username = '$username'";
    $result = $conn->query($sql);

    if ($result->num_rows > 0) {
        $row = $result->fetch_assoc();
        if (password_verify($password, $row["password"])) {
            echo "登录成功";
        } else {
            echo "密码错误";
        }
    } else {
        echo "用户名不存在";
    }
}

$conn->close();
?>

$stmt = $conn->prepare("INSERT INTO users (username, password) VALUES (?, ?)");
$stmt->bind_param("ss", $username, $hashed_password);
$stmt->execute();

$hashed_password = password_hash($password, PASSWORD_DEFAULT);