本地上传文件到服务器,从服务器下载文件到本地


最近在做项目的时候涉及到了文件的上传、下载,以前学习IO时也没有搞得多清楚,在网上找了些上传下载的例子,然后修改了部分。经测试,上传下载文件暂时能用,下面是上传和下载的方法:

1.本地上传文件到服务器

  html代码:

<form id="uploadDatumInfo" name="uploadDatumInfo" method="post" enctype="multipart/form-data" target="target_upload"><!-- 注意要加上:enctype="multipart/form-data"--> 
  <input type="file" id="datum_address" name="datum_address" class="" /> 
</form>

  js代码:

function uploadDatum()
{
     <!-- 验证上传文件是否为空 --> var datum_address=$("#datum_address").val(); if(datum_address=='') { alert("上传文件不能为空!"); return; }
<!-- 提交表单数据 --> document.uploadDatumInfo.action="<%=WebConstants.WEB_ROOT%>/saveUploadMyDatum.do?&<%=MctsUtils.getURLRandom() %>"; document.uploadDatumInfo.submit(); }

  后台代码:@Controller

@Controller
public
class MyController { @Resource(name = "MyService") private MyService myService; private ResourceManager rm = ResourceManager.getInstance(); //保存上传资料信息 @RequestMapping(value = "/saveUploadMyDatum.do") public void saveUploadMyDatum(HttpServletRequest request, HttpServletResponse response, final ModelMap context, VcDatumInfo vcDatumInfo) throws Exception { try { String myDir = rm.getValue("my_file_path"); String fileDir = rm.getValue("my_space_path"); File sourceFolder = new File(myDir + "/" + fileDir);创建存储文件夹 if (!sourceFolder.exists())
       { sourceFolder.mkdirs(); } String datum_address
= ""; DiskFileItemFactory factory = new DiskFileItemFactory(); factory.setSizeThreshold(2048 * 1024); UploadProgressListener getBarListener = new UploadProgressListener(request); ServletFileUpload upload = new ServletFileUpload(factory); upload.setProgressListener(getBarListener); List<Object> formList = upload.parseRequest(request); Iterator<Object> formItem = formList.iterator(); while (formItem.hasNext())
       { FileItem item
= (FileItem) formItem.next(); if (!item.isFormField())
          {
if (item != null && item.getSize() > 0)
            { String fieldName
= item.getFieldName(); String timeTemp = String.valueOf(new Date().getTime()); String subname = item.getName().substring( item.getName().lastIndexOf(".", item.getName().length()));//获取上传文件的后缀名 String realName = item.getName().substring(0, item.getName().lastIndexOf("."));//获取上传文件的文件名 //System.out.println(realName); if (fieldName.equals("datum_address"))
              { datum_address
= fileDir + "/" + "datum_" + timeTemp + "_" + realName + subname;//要保存到数据库中的文件地址
                
File file = new File(myDir + "/" + datum_address);//创建保存路径
                             item.write(file);//写入文件数据
                        }
                     }
                 } 
        }
      }
  } 
}

 2.从服务器下载文件

  后台代码:  

       String myDir = rm.getValue("my_file_path"); 
            OutputStream toClient = null;
            String path = "";
            path = myDir + "/" + vcDatumInfo.getDatum_address();
            try {
                // path是指欲下载的文件的路径。
                File file = new File(path);
                // 取得文件名
                String filename = file.getName();
                // 取得文件的后缀名。
                String ext = filename.substring(filename.lastIndexOf(".") + 1);
                String realName = file.getName().substring(file.getName().lastIndexOf("_") + 1, file.getName().lastIndexOf("."));//取得文件名,这一步得到的文件名有可能不是上传时的原文件名
                String realFileName = realName + "." + ext;
                // 以流的形式下载文件
                InputStream fis = new BufferedInputStream(new FileInputStream(path));
                byte[] buffer = new byte[fis.available()];
                fis.read(buffer);
                fis.close();
                // 清空response
                response.reset();
                // 设置response的Header
                response.addHeader("Content-Disposition", "attachment;filename=" + java.net.URLEncoder.encode(realFileName, "UTF-8"));//注意这一步设置文件名时,中文容易出现乱码
                response.addHeader("Content-Length", "" + file.length());
                toClient = new BufferedOutputStream(response.getOutputStream());
                response.setContentType("application/octet-stream");
                toClient.write(buffer);
                
                vcDatumInfo.setDownload_number(vcDatumInfo.getDownload_number() + 1);
                vcSpaceService.updateDatumInfo(vcDatumInfo);
                
            } catch (IOException ex) {
                ex.printStackTrace();
            }finally
            {
                if(toClient != null)
                {
                    toClient.flush();
                    toClient.close();
                }
            }

最后,感谢分享例子的作者!


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