PHP如何处理多文件上传_多文件上传功能实现教程

<form action="upload_handler.php" method="POST" enctype="multipart/form-data">
    <input type="hidden" name="MAX_FILE_SIZE" value="30000000" /> <!-- 30MB，可选但推荐 -->
    <label for="file_uploads">选择文件（可多选）:</label>
    <input type="file" name="upload_files[]" id="file_uploads" multiple="multiple">
    <button type="submit">上传</button>
</form>

<?php
if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_FILES['upload_files'])) {
    $upload_dir = 'uploads/'; // 确保这个目录存在且PHP有写入权限
    if (!is_dir($upload_dir)) {
        mkdir($upload_dir, 0755, true);
    }

    $uploaded_count = 0;
    $errors = [];

    // $_FILES['upload_files'] 实际上是一个二维数组
    // 结构大致是：
    // [
    //   'name' => ['file1.jpg', 'file2.png'],
    //   'type' => ['image/jpeg', 'image/png'],
    //   'tmp_name' => ['/tmp/phpXYZ1', '/tmp/phpXYZ2'],
    //   'error' => [0, 0],
    //   'size' => [12345, 67890]
    // ]
    // 所以我们需要通过循环索引来访问每个文件的信息

    foreach ($_FILES['upload_files']['name'] as $key => $name) {
        // 检查是否有上传错误
        if ($_FILES['upload_files']['error'][$key] !== UPLOAD_ERR_OK) {
            $errors[] = "文件 '{$name}' 上传失败，错误码: " . $_FILES['upload_files']['error'][$key];
            continue; // 跳过当前文件，处理下一个
        }

        $tmp_name = $_FILES['upload_files']['tmp_name'][$key];
        $file_size = $_FILES['upload_files']['size'][$key];
        $file_type = $_FILES['upload_files']['type'][$key];

        // --- 文件验证示例（非常重要！） ---
        $allowed_types = ['image/jpeg', 'image/png', 'image/gif'];
        $max_file_size = 5 * 1024 * 1024; // 5MB

        if (!in_array($file_type, $allowed_types)) {
            $errors[] = "文件 '{$name}' 类型不被允许。";
            continue;
        }

        if ($file_size > $max_file_size) {
            $errors[] = "文件 '{$name}' 太大，最大允许 {$max_file_size / (1024 * 1024)}MB。";
            continue;
        }

        // 确保文件名安全，防止路径遍历攻击
        $sanitized_name = basename($name); // 移除路径信息
        $destination = $upload_dir . $sanitized_name;

        // 避免文件名冲突，可以加上时间戳或唯一ID
        // $extension = pathinfo($sanitized_name, PATHINFO_EXTENSION);
        // $unique_name = uniqid() . '.' . $extension;
        // $destination = $upload_dir . $unique_name;


        // 将临时文件移动到最终位置
        if (move_uploaded_file($tmp_name, $destination)) {
            $uploaded_count++;
        } else {
            $errors[] = "文件 '{$name}' 移动失败。";
        }
    }

    if ($uploaded_count > 0) {
        echo "成功上传 {$uploaded_count} 个文件。<br>";
    }
    if (!empty($errors)) {
        echo "上传过程中出现以下问题：<br>";
        foreach ($errors as $error) {
            echo "- {$error}<br>";
        }
    }
} else {
    echo "没有文件被上传，或者请求方法不正确。";
}
?>