编写监听器以及相关的类
不用自己写了，源码可以从
http://www.telio.be/blog/2006/01/06/ajax-upload-progress-monitor-for-commons-fileupload-example里面下载，
下载地址
http://www.telio.be/blog/wp-content/uploads/2006/01/ajax-upload-1.0.war
下载完之后，你需要解包，在命令行中：
jar xvf ajax-upload-1.0.war
源码就在\WEB-INF\src下面
将要用到的文件有resources文件夹下，\WEB-INF\下面的dwr.xml和lib下面的jar文件
上传页面
在上面解开的包里面有index.jsp这个是上传页面，upload.jsp负责上传，resources包里面包含了dwr与服务器通讯的javascript脚本，你需要把index.jsp的form中的action换成你的struts action即可，然后把form中的file名改成你actionform中的file属性名，把页面中剩余的file去掉
index.jsp上传页面示例代码：
<%@ page contentType="text/html; charset=gb2312" language="java"
import="java.util.*" errorPage=""%>
<%
String path=request.getContextPath();
%>
<html locale="true">
<head>
<SCRIPT language=javascript>
function check_file() {
var strFileName=document.forms(0).file;
if (strFileName.value==""){
alert("请选择要上传的文件");
return false;
}
startProgress();
}
function loadmessage(){
<%
if (request.getAttribute("message") != null) {
%>
window.alert("<%=request.getAttribute("message")%>");
window.returnValue="yes";
<%}%>
}
</SCRIPT>
<title>上传</title>
<script src='<%=path%>/resources/js/upload.js'> </script>
<script src='<%=path%>/dwr/interface/UploadMonitor.js'> </script>
<script src='<%=path%>/dwr/engine.js'> </script>
<script src='<%=path%>/dwr/util.js'> </script>
<body leftmargin="0" topmargin="0" marginwidth="0" marginheight="0" onLoad="loadmessage()">
<form name="form" method="post" action="<%=path%>/upload.do?method=upload" enctype="multipart/form-data" onSubmit="return check_file()">
<table width="60%" border="0" cellspacing="1">
<tr background-color=" #E7F5FE">
<td width="30%" align="right">从文件导入：</td>
<td width="51%"><input type="file" name="file" class="input"></td>
<td width="27%"><input type="submit" name="files" class="button_4"
style="border-style:None;width:71px;" value="确定" id="uploadbutton">
</td>
</tr>
<tr align="left" background-color=" #E7F5FE">
<td colspan="3">
<div id="progressBar" style="display: none;">
<div id="theMeter">
<div id="progressBarText"></div>
<div id="progressBarBox">
<div id="progressBarBoxContent"></div>
</div>
</div>
</div>
</td>
</tr>
</table>
</form>
</body>
</html>
并且要修改一下\resources\js中的upload.js文件：
function refreshProgress()
{
UploadMonitor.getUploadInfo(updateProgress);
}
function updateProgress(uploadInfo)
{
if (uploadInfo.inProgress)
{
document.getElementById('uploadbutton').disabled = true;
document.getElementById('file').disabled = true;
var fileIndex = uploadInfo.fileIndex;
var progressPercent = Math.ceil((uploadInfo.bytesRead / uploadInfo.totalSize) * 100);
document.getElementById('progressBarText').innerHTML = '文件读取进度: ' progressPercent '%';
document.getElementById('progressBarBoxContent').style.width = parseInt(progressPercent * 3.5) 'px';
window.setTimeout('refreshProgress()', 1000);
}
else
{
document.getElementById('uploadbutton').disabled = false;
document.getElementById('file').disabled = false;
}
return true;
}
function startProgress()
{
document.getElementById('progressBar').style.display = 'block';
document.getElementById('progressBarText').innerHTML = '文件读取进度: 0%';
document.getElementById('uploadbutton').disabled = true;
// wait a little while to make sure the upload has started ..
window.setTimeout("refreshProgress()", 1000);
return true;
}
配置dwr.xml
放在/WEB-INF/下面
<dwr>
<allow>
<create creator="new" javascript="UploadMonitor">
<param name="class" value="be.telio.mediastore.ui.upload.UploadMonitor"/>
</create>
<convert converter="bean" match="be.telio.mediastore.ui.upload.UploadInfo"/>
</allow>
</dwr>
web.xml中配置dwr，省略spring，struts等的配置
<servlet>
<servlet-name>dwr-invoker</servlet-name>
<display-name>DWR Servlet</display-name>
<servlet-class>uk.ltd.getahead.dwr.DWRServlet</servlet-class>
<init-param>
<param-name>debug</param-name>
<param-value>false</param-value>
</init-param>
<init-param>
<param-name>logLevel</param-name>
<param-value>WARN</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>dwr-invoker</servlet-name>
<url-pattern>/dwr/*</url-pattern>
</servlet-mapping>
编写struts的MultipartRequestHandler ：AjaxMultipartRequestHandler
实现 MultipartRequestHandler接口并在struts-config.xml的controller中替换默认的multipartClass
<controller>
<set-property property="multipartClass"
value="org.springside.components.ajaxupload.AjaxMultipartRequestHandler" />
</controller>
其实这个类AjaxMultipartRequestHandler编写很简单，把struts的src源码中的org.apache.struts.upload.CommonsMultipartRequestHandler.java修改一下就可以了：
在public void handleRequest(HttpServletRequest request)
throws ServletException {
方法中把定义factory之前的那几行代码注释掉然后写入
UploadListener listener = new UploadListener(request, 30);
FileItemFactory factory = new MonitoredDiskFileItemFactory(listener);
之后再注释掉
// upload.setSizeThreshold((int) getSizeThreshold(ac));
// upload.setRepositoryPath(getRepositoryPath(ac));
这个类就算写完了
编写struts上传类
就用你原来编写的struts上传类
上传方法代码段示例：
/**
* 上传文件
*/
public ActionForward upload(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
String path = getServlet().getServletContext().getRealPath("/");
log.info(">>>>>>>>>>>>>>>path:" path);
if (form == null) {
return mapping.findForward("success");
}
FileUploadForm fuf = (FileUploadForm) form;
FormFile file = fuf.getFile();
try {
if (file == null) {
log.info(">>>>>>>>>>>>>>>file为空");
return mapping.findForward("success");
}
} catch (Exception e) {
e.printStackTrace();
}
String fname = file.getFileName();
int t = 0;
for (int i = 0; i < fname.length(); i ) {
if (fname.charAt(i) == '.') {
t = i;
} }
String filename = null;
if (t > 0) {
filename = fname.substring(0, t);
}
log.info(">>>>>>>>>>>>>>>文件名：" filename);
String filepath = path "dataimport/upfiles/" fname;
File f = new File(path "dataimport/upfiles/");
log.info(">>>>>>>>>>>>>>>文件生成路径：" filepath);
if (!f.exists()) {
f.mkdirs();
} else {
log.info(">>>>>>>>>>>>>>>路径存在");
}
InputStream stream = file.getInputStream();
OutputStream os = new FileOutputStream(path "dataimport/upfiles/"
fname);
int readBytes = 0;
byte buffer[] = new byte[8192];
while ((readBytes = stream.read(buffer, 0, 8192)) != -1) {
os.write(buffer, 0, readBytes);
}
os.close();
stream.close();
file.destroy();
String message = "成功！";
request.setAttribute("message", message);
return mapping.findForward("success");
}