java文件上传下载代码实例

@RequestMapping(value="/uploadFile",method=RequestMethod.POST) public ResultObject uploadFiles(@RequestParam("file")MultipartFile file,HttpServletRequest request){    ResultObject rs = null;//返回上传完成信息    String uploadDir = "files";//上传目录,文件保存在webapp下的files文件中   if(!file.isEmpty()) {     //可以对user做一些操作如存入数据库     //以下的代码是将文件file重新命名并存入Tomcat的webapp目录下项目的下级目录     String fileRealName = file.getOriginalFilename();          //获得原始文件名;     /*int pointIndex = fileRealName.indexOf(".");            //点号的位置     String fileSuffix = fileRealName.substring(pointIndex);       //截取文件后缀     UUID FileId = UUID.randomUUID();            //生成文件的前缀包含连字符     String savedFileName = FileId.toString().replace("-", "").concat(fileSuffix);    //文件存取名     */          String savedDir = request.getSession().getServletContext().getRealPath(uploadDir); //获取服务器指定文件存取路径     File savedFile = new File(savedDir, fileRealName);     boolean isCreateSuccess;     try {       isCreateSuccess = savedFile.createNewFile();       if (isCreateSuccess) {         file.transferTo(savedFile); //转存文件         rs = ResultObject.getSuccessResult("上传文件成功");         Long size = file.getSize();//获取文件大小         rs.setData(uploadDir+fileRealName);       }else{         rs = ResultObject.getFailResult("请修改文件名,重新上传");       }     } catch (IOException e) {       e.printStackTrace();     }   }else{     rs = ResultObject.getFailResult("文件不能为空");   }   return rs; }

@RequestMapping(value = "/filterPermission/appDownLoad", method = RequestMethod.GET)  public void appDownLoad(HttpServletRequest request, HttpServletResponse response) {    //url是上面文件上传的url    download(url,request,response);  }

public String download(String filePath, HttpServletRequest request, HttpServletResponse response) {    BufferedInputStream bis = null;    BufferedOutputStream bos = null;    try {      //获取文件名      String fileName = filePath.substring(filePath.lastIndexOf("/")+1);      response.setCharacterEncoding("utf-8");      response.setContentType("application/octet-stream");      //response.setContentType("application/force-download");      //处理下载弹出框名字的编码问题      response.setHeader("Content-Disposition", "attachment;fileName="          + new String( fileName.getBytes("gb2312"), "ISO8859-1" ));      //获取文件的下载路径      String path = request.getSession().getServletContext().getRealPath(filePath);      //利用输入输出流对文件进行下载      InputStream inputStream = new FileInputStream(new File(path));      //设置文件大小      response.setHeader("Content-Length", String.valueOf(inputStream.available()));      bis = new BufferedInputStream(inputStream);//构造读取流      bos = new BufferedOutputStream(response.getOutputStream());//构造输出流      byte[] buff = new byte[1024];      int bytesRead;      //每次读取缓存大小的流，写到输出流      while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {        bos.write(buff, 0, bytesRead);      }      response.flushBuffer();//将所有的读取的流返回给客户端    } catch (FileNotFoundException e) {      e.printStackTrace();    } catch (IOException e) {      e.printStackTrace();    }finally{      try{        if(null != bis){          bis.close();        }        if(null != bos){          bos.close();        }      }catch(IOException e){        System.out.println("下载文件失败,"+"文件路径:"+filePath+e);        logger.error("文件下载失败!", e);      }    }    // 返回值要注意，要不然就出现下面这句错误！    //java+getOutputStream() has already been called for this response    return null;  }