java文件上传下载

<form  action="${pageContext.request.contextPath}/UploadHandleServlet"  method="post"  enctype="multipart/form-data">
上传用户x：<input type="text" name="username"><br/>
上传文件1：<input type="file" name="file1"><br/>
<input type="submit" value="提交">
</form>

SimpleDateFormat sdf1 = new SimpleDateFormat("yyyyMMddHHmmss");
String savePath =request.getSession().getServletContext().getRealPath("/WEB-INF/upload");
File file = new File(savePath);
if (!file.exists()) {
file.mkdir();
}
String message ="";
try{
DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setSizeThreshold(1024*100);
factory.setRepository(file);

ServletFileUpload upload = new ServletFileUpload(factory);
upload.setHeaderEncoding("UTF-8");
List<FileItem> list = upload.parseRequest(request);

//正则匹配，过滤路径取文件名
String regExp = ".+\\\\(.+)$";
Pattern p = Pattern.compile(regExp);

String fileName="";
for(FileItem item : list){
if(item.isFormField()){
String name = item.getFieldName();
String value = item.getString("UTF-8");
System.out.println(name + "=" + value);
}else{
String name = item.getName();
name = name.substring(name.lastIndexOf("\\")+1);
fileName = savePath+"/"+ sdf1.format(new Date()) + "_"+name;
item.write(new File(fileName));
}

}
message = "文件上传成功！";
}catch (Exception e) {
message= "文件上传失败！";
e.printStackTrace();
}

//获得文件名和文件路径
String name = map.get("name")+"";
String path = map.get("path")+"";

String filename= new String(name.getBytes("utf-8"),"iso8859-1");

File file = new File(path);
InputStream fis = new BufferedInputStream(new FileInputStream(path));
byte[] buffer = new byte[fis.available()];
fis.read(buffer);
fis.close();
response.reset();
response.addHeader("Content-Disposition", "attachment;filename=" + new String(name.replaceAll(" ", "").getBytes("utf-8"),"iso8859-1"));
response.addHeader("Content-Length", "" + file.length());
OutputStream os = new BufferedOutputStream(response.getOutputStream());
response.setContentType("application/octet-stream");
os.write(buffer);// 输出文件
os.flush();
os.close();