一步步教你用PHP开发自己的论坛网站

<?php
    // 连接数据库
    $conn = mysqli_connect('localhost', 'root', 'passWord', 'forum');

    // 接收用户提交的表单数据
    $username = $_POST['username'];
    $password = $_POST['password'];
    $email = $_POST['email'];

    // 将用户信息插入到数据库中
    $sql = "INSERT INTO users (username, password, email) VALUES ('$username', '$password', '$email')";
    mysqli_query($conn, $sql);

    // 关闭数据库连接
    mysqli_close($conn);
?>

<?php
    // 连接数据库
    $conn = mysqli_connect('localhost', 'root', 'password', 'forum');

    // 接收用户提交的表单数据
    $username = $_POST['username'];
    $password = $_POST['password'];

    // 查询数据库，验证用户输入的信息是否正确
    $sql = "SELECT * FROM users WHERE username='$username' AND password='$password'";
    $result = mysqli_query($conn, $sql);

    if (mysqli_num_rows($result) > 0) {
        // 验证通过，将用户信息保存到Session中
        session_start();
        $_SESSION['username'] = $username;

        // 跳转到论坛首页
        header('Location: index.php');
        exit();
    } else {
        // 验证失败，返回登录页面并显示错误信息
        header('Location: login.php?error=1');
        exit();
    }

    // 关闭数据库连接
    mysqli_close($conn);
?>

<?php
    // 连接数据库
    $conn = mysqli_connect('localhost', 'root', 'password', 'forum');

    // 接收用户提交的表单数据
    $title = $_POST['title'];
    $content = $_POST['content'];
    $author = $_SESSION['username'];

    // 将帖子信息插入到数据库中
    $sql = "INSERT INTO posts (title, content, author) VALUES ('$title', '$content', '$author')";
    mysqli_query($conn, $sql);

    // 关闭数据库连接
    mysqli_close($conn);
?>

<?php
    // 连接数据库
    $conn = mysqli_connect('localhost', 'root', 'password', 'forum');

    // 接收用户提交的表单数据
    $content = $_POST['content'];
    $author = $_SESSION['username'];
    $post_id = $_POST['post_id'];

    // 将回复信息插入到数据库中
    $sql = "INSERT INTO replies (content, author, post_id) VALUES ('$content', '$author', '$post_id')";
    mysqli_query($conn, $sql);

    // 关闭数据库连接
    mysqli_close($conn);
?>

<?php
    // 连接数据库
    $conn = mysqli_connect('localhost', 'root', 'password', 'forum');

    // 查询数据库，获取帖子信息
    $sql = "SELECT * FROM posts";
    $result = mysqli_query($conn, $sql);

    // 遍历结果集并显示帖子信息
    while ($row = mysqli_fetch_assoc($result)) {
        echo '<h2><a href="post.php?id=' . $row['id'] . '">' . $row['title'] . '</a></h2>';
        echo '<p>' . $row['content'] . '</p>';
        echo '<hr>';
    }

    // 关闭数据库连接
    mysqli_close($conn);
?>