java web 中上传文件和下载文件代码片段

/**
* Purpose：上传文档
*
* @param req
* @param fileTitle
* @param fileType
* @param fileDesc
* @return
*/
@RequestMapping("upload")
public ModelAndView upload(HttpServletRequest req, String fileType, String fileDesc, String share) {
UserAllInfo userAll = (UserAllInfo) req.getSession().getAttribute("userAll");
ModelAndView mav = new ModelAndView();
// 获取文件的大小
String fileSize = "";
int length = req.getContentLength();
//转换成KB
double len1 = (double) (Math.round((length / 1024) * 100)) / 100;
//转换成MB
double len2 = (double) (Math.round((len1 / 1024) * 100)) / 100;
if (len2 > 1) {
fileSize = String.valueOf(len2) + "MB";
} else {
fileSize = String.valueOf(len1) + "KB";
}
//将请求转换成处理文件的请求
MultipartRequest mreq = (MultipartRequest) req;
//文件上传专用类
MultipartFile mfile = mreq.getFile("uploadFile");

// 得到上下文路径
String root = req.getSession().getServletContext().getRealPath("/");
File dir = new File(root);
// 获取文件名和文件的mime类型
String str = mfile.getOriginalFilename();
String[] st = str.split("\\.");

File savedFile = null;
try {
//在指定目录中创建一个新的空文件，文件名称加前缀"upload_"
savedFile = File.createTempFile("upload_", mfile.getOriginalFilename(), dir);
//将缓冲区的内容复制到新创建的文件中
FileCopyUtils.copy(mfile.getInputStream(), new FileOutputStream(savedFile));
} catch (Exception e) {
e.printStackTrace();
}
String path = savedFile.getPath();

// 将文件的信息封装在对象中
FileInfo file = new FileInfo();
if (userAll != null) {
file.setUploadPersonId(userAll.getUser().getUserId());
} else {
mav.setViewName("login");
return mav;
}
file.setFileName(st[0]);
file.setFilePath(path);
Date date = new Date();
file.setUploadDate(date);
file.setFileSize(fileSize);
file.setFileType(fileType);
file.setFileForm(st[1]);
if ("superman".equals(userAll.getUser().getUserNumber())) {
file.setFileShare("Y");
file.setCheckFlag("Y");
} else {
file.setFileShare(share);
file.setCheckFlag("N");
}
file.setDeleteFlag("N");
file.setDownloadTimes(0);
// 保存文件的信息
boolean bool = fileSer.saveFile(file);
String userNumber = userAll.getUser().getUserNumber();
//设置跳转界面
mav.setViewName("jsp/person/upload");
logSer.saveLog("用户\"" + userNumber + "\"上传文件\"" + file.getFileName() + "\"");
mav.getModel().put("bool", bool);
return mav;
}

/**
* Purpose：下载文档
*
* @param fileId 文件id
* @return
*/
@RequestMapping("download")
public void download(Integer fileId, HttpServletResponse resp) {
FileInfo file = new FileInfo();
//通过文件id获取文件的基本信息
file = fileSer.getFileById(fileId);

// 根据文件后缀名设置文件的mime类型
String mime = "application/";
switch (file.getFileForm()) {
case "doc":
mime = mime + "msword";
break;
case "docx":
mime = mime + "msword";
break;
case "pdf":
mime = mime + "pdf";
break;
case "xls":
mime = mime + "vnd.ms-excel";
case "ppt":
mime = mime + "vnd.ms-powerpoint";
break;
case "txt":
mime = "text/plain";
break;
default:
break;
}
resp.setContentType(mime);
String fileName = file.getFileName();
String name = "";
try {
// 将文件名使用utf-8编码格式编码，使其中的中文字符可以正常显示
name = URLEncoder.encode(fileName, "utf-8");
} catch (UnsupportedEncodingException e1) {
e1.printStackTrace();
}

// 弹框选择保存路径
resp.setHeader("content-disposition", "attachment;filename=" + name + "." + file.getFileForm()
+ ";filename*=utf-8''" + name + "." + file.getFileForm());

String filePath = file.getFilePath();
InputStream is = null;
OutputStream os = null;
try {
is = new BufferedInputStream(new FileInputStream(filePath));
os = new BufferedOutputStream(resp.getOutputStream());
byte[] buff = new byte[1024];
@SuppressWarnings("unused")
int count;
while ((count = is.read(buff)) != -1) {
os.write(buff);
}
//修改下载次数
fileSer.update(fileId);
} catch (Exception e) {
e.printStackTrace();
} finally {
//最后，要记得关闭输入流和输出流
if (is != null) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (os != null) {
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}