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php 实现评论

2026-01-15 12:10:21PHP

实现 PHP 评论功能

数据库设计

创建数据库表存储评论数据，通常包含以下字段：

id：评论唯一标识
user_id：用户ID
content：评论内容
created_at：评论时间
parent_id：回复的父评论ID（用于嵌套评论）

SQL 创建表示例：

CREATE TABLE comments (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT NOT NULL,
    content TEXT NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    parent_id INT DEFAULT NULL,
    FOREIGN KEY (parent_id) REFERENCES comments(id) ON DELETE CASCADE
);

前端表单

创建评论提交表单：

<form action="submit_comment.php" method="post">
    <textarea name="content" required></textarea>
    <input type="hidden" name="parent_id" value="0">
    <button type="submit">提交评论</button>
</form>

处理评论提交

创建 submit_comment.php 处理表单提交：

<?php
// 连接数据库
$db = new PDO('mysql:host=localhost;dbname=your_db', 'username', 'password');

// 获取表单数据
$content = htmlspecialchars($_POST['content']);
$parent_id = intval($_POST['parent_id']);
$user_id = $_SESSION['user_id']; // 假设用户已登录

// 插入评论
$stmt = $db->prepare("INSERT INTO comments (user_id, content, parent_id) VALUES (?, ?, ?)");
$stmt->execute([$user_id, $content, $parent_id]);

// 重定向回评论页面
header('Location: comments.php');
?>

显示评论

创建 comments.php 显示评论列表：

<?php
// 连接数据库
$db = new PDO('mysql:host=localhost;dbname=your_db', 'username', 'password');

// 获取顶级评论
$stmt = $db->query("SELECT * FROM comments WHERE parent_id = 0 ORDER BY created_at DESC");
$comments = $stmt->fetchAll(PDO::FETCH_ASSOC);

// 递归函数获取回复
function getReplies($comment_id, $db) {
    $stmt = $db->prepare("SELECT * FROM comments WHERE parent_id = ? ORDER BY created_at ASC");
    $stmt->execute([$comment_id]);
    $replies = $stmt->fetchAll(PDO::FETCH_ASSOC);

    foreach ($replies as &$reply) {
        $reply['replies'] = getReplies($reply['id'], $db);
    }

    return $replies;
}

// 为每条评论添加回复
foreach ($comments as &$comment) {
    $comment['replies'] = getReplies($comment['id'], $db);
}
?>

<!-- 显示评论 -->
<div class="comments">
    <?php foreach ($comments as $comment): ?>
        <div class="comment">
            <p><?= $comment['content'] ?></p>
            <small>Posted by user <?= $comment['user_id'] ?></small>

            <!-- 回复表单 -->
            <form action="submit_comment.php" method="post">
                <textarea name="content" required></textarea>
                <input type="hidden" name="parent_id" value="<?= $comment['id'] ?>">
                <button type="submit">回复</button>
            </form>

            <!-- 显示回复 -->
            <div class="replies">
                <?php foreach ($comment['replies'] as $reply): ?>
                    <div class="reply">
                        <p><?= $reply['content'] ?></p>
                        <small>Posted by user <?= $reply['user_id'] ?></small>
                    </div>
                <?php endforeach; ?>
            </div>
        </div>
    <?php endforeach; ?>
</div>