java文件上传下载

文件上传

  @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;
  }

文件下载

@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;
    }