下面通过一段代码给大家演示下，主要分为1.前台文件index.html和 2.后台文件upload.php。具体代码如下所示：

1.前台文件index.html

var swfu;

window.onload = function() {

var settings = {

flash_url : "swfupload/swfupload.swf",

upload_url: "upload.php", // 后台文件

post_params: {"PHPSESSID" : "<?php echo session_id(); ?>"},

file_size_limit : "100 MB",

file_types : "*.*",

file_types_description : "All Files",

file_upload_limit : 100,

file_queue_limit : 0,

custom_settings : {

progressTarget : "fsUploadProgress",

cancelButtonId : "btnCancel"

},

debug: false,

// 按钮设置

button_image_url: "images/TestImageNoText_65x29.png", // Flash样式图片文件

button_width: "65",

button_height: "29",

button_placeholder_id: "spanButtonPlaceHolder",

button_text: '浏览',

button_text_style: ".theFont { font-size: 16; }",

button_text_left_padding: 12,

button_text_top_padding: 3,

// 句柄设置

file_queued_handler : fileQueued,

file_queue_error_handler : fileQueueError,

file_dialog_complete_handler : fileDialogComplete,

upload_start_handler : uploadStart,

upload_progress_handler : uploadProgress,

upload_error_handler : uploadError,

upload_success_handler : uploadSuccess,

upload_complete_handler : uploadComplete,

queue_complete_handler : queueComplete

};

swfu = new SWFUpload(settings);

};

2.后台文件upload.php

// 传递session值(由于Flash与session不兼容，只能通过参数传递获取)

if (isset($_POST["PHPSESSID"])) {

session_id($_POST["PHPSESSID"]);

} else if (isset($_GET["PHPSESSID"])) {

session_id($_GET["PHPSESSID"]);

}

session_start();

// 设置POST最大值

$POST_MAX_SIZE = ini_get('post_max_size');

$unit = strtoupper(substr($POST_MAX_SIZE, -1));

$multiplier = ($unit == 'M' ? 1048576 : ($unit == 'K' ? 1024 : ($unit == 'G' ? 1073741824 : 1)));

if ((int)$_SERVER['CONTENT_LENGTH'] > $multiplier*(int)$POST_MAX_SIZE && $POST_MAX_SIZE) {

header("HTTP/1.1 500 Internal Server Error");

echo "POST exceeded maximum allowed size.";

exit(0);

}

// 基本设置

$save_path = getcwd() . "/file/"; 　　　　　　　　　　　　// 文件上传位置

$upload_name = "Filedata";

$max_file_size_in_bytes = 2147483647; 　　　　　　　　　// 2GB

$extension_whitelist = array("doc", "txt", "jpg", "gif", "png"); // 允许文件类型

$valid_chars_regex = '.A-Z0-9_ !@#$%^&()+={}\[\]\',~`-'; // 文件名规则

// 其他变量

$MAX_FILENAME_LENGTH = 260;

$file_name = "";

$file_extension = "";

$uploadErrors = array(

0=>"文件上传成功",

1=>"上传的文件超过了 php.ini 文件中的 upload_max_filesize directive 里的设置",

2=>"上传的文件超过了 HTML form 文件中的 MAX_FILE_SIZE directive 里的设置",

3=>"上传的文件仅为部分文件",

4=>"没有文件上传",

6=>"缺少临时文件夹"

);

// 检测文件是否上传正确

if (!isset($_FILES[$upload_name])) {

HandleError("No upload found in \$_FILES for " . $upload_name);

exit(0);

} else if (isset($_FILES[$upload_name]["error"]) && $_FILES[$upload_name]["error"] != 0) {

HandleError($uploadErrors[$_FILES[$upload_name]["error"]]);

exit(0);

} else if (!isset($_FILES[$upload_name]["tmp_name"]) || !@is_uploaded_file($_FILES[$upload_name]["tmp_name"])) {

HandleError("Upload failed is_uploaded_file test.");

exit(0);

} else if (!isset($_FILES[$upload_name]['name'])) {

HandleError("File has no name.");

exit(0);

}

// 检测文件尺寸

$file_size = @filesize($_FILES[$upload_name]["tmp_name"]);

if (!$file_size || $file_size > $max_file_size_in_bytes) {

HandleError("File exceeds the maximum allowed size");

exit(0);

}

if ($file_size <= 0) {

HandleError("File size outside allowed lower bound");

exit(0);

}

// 检测文件名字为空

$file_name = preg_replace('/[^'.$valid_chars_regex.']|\.+$/i', "", basename($_FILES[$upload_name]['name']));

if (strlen($file_name) == 0 || strlen($file_name) > $MAX_FILENAME_LENGTH) {

HandleError("Invalid file name");

exit(0);

}

// 检测重名文件

if (file_exists($save_path . $file_name)) {

HandleError("File with this name already exists");

exit(0);

}

// 检测后缀名

$path_info = pathinfo($_FILES[$upload_name]['name']);

$file_extension = $path_info["extension"];

$is_valid_extension = false;

foreach ($extension_whitelist as $extension) {

if (strcasecmp($file_extension, $extension) == 0) {

$is_valid_extension = true;

break;

}

}

if (!$is_valid_extension) {

HandleError("Invalid file extension");

exit(0);

}

// 保存文件

if (!@move_uploaded_file($_FILES[$upload_name]["tmp_name"], $save_path.$file_name)) {

HandleError("文件无法保存.");

exit(0);

}

// 成功输出

echo "File Received";

exit(0);

function HandleError($message) {

header("HTTP/1.1 500 Internal Server Error");

echo $message;

}

?>

以上代码就是实现文件上传之SwFUpload插件的全部内容，希望大家喜欢。