php评论功能实现
数据库设计
创建评论表（comments）存储评论数据，字段通常包括id、content、user_id、article_id、created_at等。示例SQL：
CREATE TABLE comments (
id INT AUTO_INCREMENT PRIMARY KEY,
content TEXT NOT NULL,
user_id INT NOT NULL,
article_id INT NOT NULL,
created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
FOREIGN KEY (user_id) REFERENCES users(id),
FOREIGN KEY (article_id) REFERENCES articles(id)
);表单提交处理
创建HTML表单提交评论内容，后端用PHP接收处理。示例表单代码：
<form action="submit_comment.php" method="POST">
<textarea name="content" required></textarea>
<input type="hidden" name="article_id" value="<?php echo $article_id; ?>">
<button type="submit">提交评论</button>
</form>后端处理逻辑
在submit_comment.php中处理表单提交并存入数据库：
<?php
session_start();
require 'db_connection.php';
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
$content = htmlspecialchars($_POST['content']);
$article_id = (int)$_POST['article_id'];
$user_id = $_SESSION['user_id'];
$stmt = $pdo->prepare("INSERT INTO comments (content, user_id, article_id) VALUES (?, ?, ?)");
$stmt->execute([$content, $user_id, $article_id]);
header("Location: article.php?id=$article_id");
exit;
}
?>评论显示功能
在文章页面查询并显示相关评论：
<?php
$article_id = (int)$_GET['id'];
$stmt = $pdo->prepare("SELECT c.*, u.username FROM comments c
JOIN users u ON c.user_id = u.id
WHERE article_id = ? ORDER BY created_at DESC");
$stmt->execute([$article_id]);
$comments = $stmt->fetchAll();
foreach ($comments as $comment) {
echo '<div class="comment">';
echo '<strong>' . htmlspecialchars($comment['username']) . '</strong>';
echo '<p>' . htmlspecialchars($comment['content']) . '</p>';
echo '<small>' . $comment['created_at'] . '</small>';
echo '</div>';
}
?>安全防护措施
对用户输入进行过滤和验证：
// 使用预处理语句防止SQL注入
$stmt = $pdo->prepare("INSERT INTO comments (...) VALUES (?, ?, ?)");
// 输出时转义特殊字符
echo htmlspecialchars($user_input);
// 验证用户权限
if (!isset($_SESSION['user_id'])) {
die('请登录后评论');
}分页功能实现
对大量评论实现分页显示：
$per_page = 10;
$page = isset($_GET['page']) ? (int)$_GET['page'] : 1;
$offset = ($page - 1) * $per_page;
$stmt = $pdo->prepare("SELECT SQL_CALC_FOUND_ROWS * FROM comments
WHERE article_id = ? LIMIT $offset, $per_page");
$stmt->execute([$article_id]);
$total = $pdo->query("SELECT FOUND_ROWS()")->fetchColumn();
$total_pages = ceil($total / $per_page);
