php分片上传代码（php分片下载）

以下是一个简单的PHP分片上传代码示例：

<?php
$targetDir = "uploads/"; // 上传目录
$chunkDir = "chunks/"; // 分片目录

if (!empty($_FILES) && isset($_POST['chunkIndex']) && isset($_POST['totalChunks']) && isset($_POST['fileName'])) {
    $chunkIndex = $_POST['chunkIndex'];
    $totalChunks = $_POST['totalChunks'];
    $fileName = $_POST['fileName'];

    // 创建分片目录
    if (!file_exists($chunkDir)) {
        mkdir($chunkDir, 0777, true);
    }

    // 保存分片文件
    $tempFilePath = $chunkDir . $fileName . '_' . $chunkIndex;
    move_uploaded_file($_FILES['file']['tmp_name'], $tempFilePath);

    // 检查是否已上传所有分片
    for ($i = 0; $i < $totalChunks; $i++) {
        if (!file_exists($chunkDir . $fileName . '_' . $i)) {
            die('{"status":"incomplete"}');
        }
    }

    // 合并所有分片
    $targetFilePath = $targetDir . $fileName;
    $targetFile = fopen($targetFilePath, 'wb');
    for ($i = 0; $i < $totalChunks; $i++) {
        $chunkFilePath = $chunkDir . $fileName . '_' . $i;
        $chunkFile = fopen($chunkFilePath, 'rb');
        stream_copy_to_stream($chunkFile, $targetFile);
        fclose($chunkFile);
        unlink($chunkFilePath);
    }
    fclose($targetFile);

    echo '{"status":"success"}';
} else {
    echo '{"status":"error"}';
}
?>

以下是一个简单的PHP分片下载代码示例：

<?php
$filePath = "path/to/file"; // 文件路径
$chunkSize = 1024 * 1024; // 分片大小（1MB）

if (file_exists($filePath)) {
    $fileSize = filesize($filePath);
    $handle = fopen($filePath, 'rb');

    header("Content-Type: application/octet-stream");
    header("Content-Disposition: attachment; filename=\"" . basename($filePath) . "\"");
    header("Content-Length: " . $fileSize);

    $bytesSent = 0;
    while (!feof($handle) && !connection_aborted()) {
        $chunk = fread($handle, $chunkSize);
        echo $chunk;
        $bytesSent += strlen($chunk);
        flush();
    }

    fclose($handle);
} else {
    echo "File not found.";
}
?>

注意：以上代码仅为示例，可能需要根据实际需求进行修改和优化。