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php实现评论功能

2026-01-15 12:59:05PHP

数据库设计

创建评论表（示例结构）：

CREATE TABLE `comments` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `user_id` int(11) NOT NULL,
  `content` text NOT NULL,
  `created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `parent_id` int(11) DEFAULT NULL COMMENT '回复的评论ID',
  `post_id` int(11) NOT NULL COMMENT '关联的文章或内容ID',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

表单提交处理

创建评论提交表单（HTML部分）：

<form action="submit_comment.php" method="POST">
  <input type="hidden" name="post_id" value="<?php echo $post_id; ?>">
  <textarea name="content" required></textarea>
  <button type="submit">提交评论</button>
</form>

PHP处理逻辑（submit_comment.php）：

<?php
session_start();
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
  $content = htmlspecialchars($_POST['content']);
  $post_id = intval($_POST['post_id']);
  $user_id = $_SESSION['user_id'] ?? 0; // 假设用户已登录

  $pdo = new PDO('mysql:host=localhost;dbname=test', 'username', 'password');
  $stmt = $pdo->prepare("INSERT INTO comments (user_id, content, post_id) VALUES (?, ?, ?)");
  $stmt->execute([$user_id, $content, $post_id]);

  header("Location: post.php?id=".$post_id); // 返回原页面
}
?>

评论列表展示

从数据库查询并显示评论：

<?php
$post_id = intval($_GET['id']);
$pdo = new PDO('mysql:host=localhost;dbname=test', 'username', 'password');
$stmt = $pdo->prepare("SELECT * FROM comments WHERE post_id = ? ORDER BY created_at DESC");
$stmt->execute([$post_id]);
$comments = $stmt->fetchAll(PDO::FETCH_ASSOC);

foreach ($comments as $comment) {
  echo '<div class="comment">';
  echo '<p>'.htmlspecialchars($comment['content']).'</p>';
  echo '<small>用户ID: '.$comment['user_id'].' | 时间: '.$comment['created_at'].'</small>';
  echo '</div>';
}
?>

回复功能实现

扩展表单支持回复：

<form action="submit_comment.php" method="POST">
  <input type="hidden" name="post_id" value="<?php echo $post_id; ?>">
  <input type="hidden" name="parent_id" value="<?php echo $_GET['reply_to'] ?? 0; ?>">
  <textarea name="content" required></textarea>
  <button type="submit">提交</button>
</form>

更新数据库插入逻辑：

$parent_id = isset($_POST['parent_id']) ? intval($_POST['parent_id']) : null;
$stmt = $pdo->prepare("INSERT INTO comments (user_id, content, post_id, parent_id) VALUES (?, ?, ?, ?)");
$stmt->execute([$user_id, $content, $post_id, $parent_id]);

嵌套评论展示

递归显示评论及回复：

function displayComments($comments, $parent_id = null) {
  foreach ($comments as $comment) {
    if ($comment['parent_id'] == $parent_id) {
      echo '<div class="comment" style="margin-left: '.($parent_id ? '20px' : '0').'">';
      echo '<p>'.htmlspecialchars($comment['content']).'</p>';
      echo '<a href="?id='.$comment['post_id'].'&reply_to='.$comment['id'].'">回复</a>';
      displayComments($comments, $comment['id']); // 递归调用
      echo '</div>';
    }
  }
}
displayComments($comments);