留言板具有用户注册 用户登录 留言查看 留言发布 留言删除 留言编辑的功能的php代码

以下是一个简单的留言板的 PHP 代码，包括用户注册、用户登录、留言查看、留言发布、留言删除和留言编辑的功能：

1. 用户注册

<?php
// 连接数据库
$con = mysqli_connect("localhost", "root", "", "message_board");

// 处理表单提交
if(isset($_POST['submit'])){
    // 获取表单数据
    $username = mysqli_real_escape_string($con, $_POST['username']);
    $password = mysqli_real_escape_string($con, $_POST['password']);
    $email = mysqli_real_escape_string($con, $_POST['email']);

    // 将数据插入数据库
    $sql = "INSERT INTO users (username, password, email) VALUES ('$username', '$password', '$email')";
    mysqli_query($con, $sql);
    echo "注册成功！";
}
?>
<!-- 注册表单 -->
<form method="post">
    <input type="text" name="username" placeholder="用户名" required>
    <input type="password" name="password" placeholder="密码" required>
    <input type="email" name="email" placeholder="邮箱" required>
    <input type="submit" name="submit" value="注册">
</form>

2. 用户登录

<?php
// 连接数据库
$con = mysqli_connect("localhost", "root", "", "message_board");

// 处理表单提交
if(isset($_POST['submit'])){
    // 获取表单数据
    $username = mysqli_real_escape_string($con, $_POST['username']);
    $password = mysqli_real_escape_string($con, $_POST['password']);

    // 查询用户信息
    $sql = "SELECT * FROM users WHERE username='$username' AND password='$password'";
    $result = mysqli_query($con, $sql);

    // 验证用户信息
    if(mysqli_num_rows($result) == 1){
        echo "登录成功！";
        session_start();
        $_SESSION['username'] = $username;
        header('Location: index.php'); // 跳转到留言板首页
    } else {
        echo "用户名或密码错误！";
    }
}
?>
<!-- 登录表单 -->
<form method="post">
    <input type="text" name="username" placeholder="用户名" required>
    <input type="password" name="password" placeholder="密码" required>
    <input type="submit" name="submit" value="登录">
</form>

3. 留言查看

<?php
// 连接数据库
$con = mysqli_connect("localhost", "root", "", "message_board");

// 查询留言
$sql = "SELECT * FROM messages ORDER BY id DESC";
$result = mysqli_query($con, $sql);

// 显示留言
while($row = mysqli_fetch_assoc($result)){
    echo "<div>";
    echo "<h3>{$row['title']}</h3>";
    echo "<p>{$row['content']}</p>";
    echo "<p>作者：{$row['author']}</p>";
    echo "<p>发布时间：{$row['created_at']}</p>";
    echo "</div>";
}
?>

4. 留言发布

<?php
// 连接数据库
$con = mysqli_connect("localhost", "root", "", "message_board");

// 处理表单提交
if(isset($_POST['submit'])){
    // 获取表单数据
    $title = mysqli_real_escape_string($con, $_POST['title']);
    $content = mysqli_real_escape_string($con, $_POST['content']);
    session_start();
    $author = $_SESSION['username'];

    // 将数据插入数据库
    $sql = "INSERT INTO messages (title, content, author) VALUES ('$title', '$content', '$author')";
    mysqli_query($con, $sql);
    echo "发布成功！";
}
?>
<!-- 发布留言表单 -->
<form method="post">
    <input type="text" name="title" placeholder="标题" required>
    <textarea name="content" placeholder="内容" required></textarea>
    <input type="submit" name="submit" value="发布">
</form>

5. 留言删除

<?php
// 连接数据库
$con = mysqli_connect("localhost", "root", "", "message_board");

// 处理删除请求
if(isset($_GET['delete'])){
    $id = mysqli_real_escape_string($con, $_GET['delete']);

    // 删除留言
    $sql = "DELETE FROM messages WHERE id=$id";
    mysqli_query($con, $sql);
    echo "删除成功！";
}

// 查询留言
$sql = "SELECT * FROM messages ORDER BY id DESC";
$result = mysqli_query($con, $sql);

// 显示留言和删除链接
while($row = mysqli_fetch_assoc($result)){
    echo "<div>";
    echo "<h3>{$row['title']}</h3>";
    echo "<p>{$row['content']}</p>";
    echo "<p>作者：{$row['author']}</p>";
    echo "<p>发布时间：{$row['created_at']}</p>";
    // 删除链接
    echo "<a href='index.php?delete={$row['id']}'>删除</a>";
    echo "</div>";
}
?>

6. 留言编辑

<?php
// 连接数据库
$con = mysqli_connect("localhost", "root", "", "message_board");

// 处理编辑请求
if(isset($_POST['edit'])){
    $id = mysqli_real_escape_string($con, $_POST['id']);
    $title = mysqli_real_escape_string($con, $_POST['title']);
    $content = mysqli_real_escape_string($con, $_POST['content']);

    // 更新留言
    $sql = "UPDATE messages SET title='$title', content='$content' WHERE id=$id";
    mysqli_query($con, $sql);
    echo "编辑成功！";
}

// 处理编辑表单提交
if(isset($_GET['edit'])){
    $id = mysqli_real_escape_string($con, $_GET['edit']);

    // 查询留言
    $sql = "SELECT * FROM messages WHERE id=$id";
    $result = mysqli_query($con, $sql);
    $row = mysqli_fetch_assoc($result);

    // 显示编辑表单
    echo "<form method='post'>";
    echo "<input type='hidden' name='id' value='{$row['id']}'>";
    echo "<input type='text' name='title' value='{$row['title']}' required>";
    echo "<textarea name='content' required>{$row['content']}</textarea>";
    echo "<input type='submit' name='edit' value='保存'>";
    echo "</form>";
}

// 查询留言
$sql = "SELECT * FROM messages ORDER BY id DESC";
$result = mysqli_query($con, $sql);

// 显示留言和编辑链接
while($row = mysqli_fetch_assoc($result)){
    echo "<div>";
    echo "<h3>{$row['title']}</h3>";
    echo "<p>{$row['content']}</p>";
    echo "<p>作者：{$row['author']}</p>";
    echo "<p>发布时间：{$row['created_at']}</p>";
    // 编辑链接
    echo "<a href='index.php?edit={$row['id']}'>编辑</a>";
    echo "</div>";
}
?>