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php实现点赞

2026-04-02 22:02:18PHP

实现点赞功能的基本思路

点赞功能通常涉及前端交互和后端数据处理。前端负责用户点击触发，后端处理数据存储和更新。以下是实现点赞功能的常见方法。

数据库设计

创建数据表存储点赞信息，例如：

CREATE TABLE likes (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT NOT NULL,
    post_id INT NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    UNIQUE KEY (user_id, post_id)
);

user_id和post_id组合唯一约束防止重复点赞。

后端PHP处理

创建点赞接口处理请求：

<?php
header('Content-Type: application/json');

// 假设已连接数据库
$pdo = new PDO('mysql:host=localhost;dbname=test', 'username', 'password');

$userId = $_POST['user_id'] ?? 0;
$postId = $_POST['post_id'] ?? 0;

// 验证输入
if (!$userId || !$postId) {
    echo json_encode(['success' => false, 'message' => 'Invalid input']);
    exit;
}

try {
    // 检查是否已点赞
    $stmt = $pdo->prepare("SELECT id FROM likes WHERE user_id = ? AND post_id = ?");
    $stmt->execute([$userId, $postId]);

    if ($stmt->fetch()) {
        // 已点赞，执行取消
        $pdo->prepare("DELETE FROM likes WHERE user_id = ? AND post_id = ?")->execute([$userId, $postId]);
        echo json_encode(['success' => true, 'action' => 'unlike']);
    } else {
        // 未点赞，执行点赞
        $pdo->prepare("INSERT INTO likes (user_id, post_id) VALUES (?, ?)")->execute([$userId, $postId]);
        echo json_encode(['success' => true, 'action' => 'like']);
    }
} catch (PDOException $e) {
    echo json_encode(['success' => false, 'message' => $e->getMessage()]);
}

前端实现

使用AJAX发送点赞请求：

function toggleLike(postId, userId) {
    fetch('like.php', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/x-www-form-urlencoded',
        },
        body: `user_id=${userId}&post_id=${postId}`
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
            const button = document.querySelector(`.like-btn[data-post="${postId}"]`);
            if (data.action === 'like') {
                button.classList.add('liked');
                button.textContent = 'Unlike';
            } else {
                button.classList.remove('liked');
                button.textContent = 'Like';
            }
        }
    });
}

获取点赞数量

添加获取点赞数量的接口：

<?php
header('Content-Type: application/json');

$postId = $_GET['post_id'] ?? 0;

if (!$postId) {
    echo json_encode(['success' => false]);
    exit;
}

try {
    $stmt = $pdo->prepare("SELECT COUNT(*) as count FROM likes WHERE post_id = ?");
    $stmt->execute([$postId]);
    $result = $stmt->fetch();
    echo json_encode(['success' => true, 'count' => $result['count']]);
} catch (PDOException $e) {
    echo json_encode(['success' => false]);
}