下载的zip文件返回零，具有0字节的大小 [英] downloaded zip file returns zero has 0 bytes as size

问题描述

我写了一个Java Web应用程序，允许用户从服务器下载文件。这些文件是相当大的，所以在下载之前压缩在一起。

它的工作原理如下：

1.用户获得与他/她的标准相符的文件列表
2.如果用户喜欢文件，并希望下载他/她通过选中复选框
3.选择它。用户然后点击下载

4.文件然后压缩并存储在服务器上a
5.然后用户显示一个包含可下载zip文件的链接的页面a
6.但是下载zip文件下载的文件大小为0个字节

我已经检查了远程服务器，正在正确创建zip文件，剩下的就是以某种方式向用户提供文件，您可以看到我可能会出错，还是建议更好的方式来提供zip文件。

创建链接的代码是：

 <％
 String zipFileURL =（String）request.getAttribute（zipFileURL）; ％GT; 
< p>< a href =<％out.print（zipFileURL）;％>> Zip文件链接< / a>< / p> 
  

创建zipFileURL变量的代码是：

  public static String zipFiles（ArrayList< String> fileList，String contextRootPath）{
 // time-stamping 
 Date date = new Date（）; 
 Timestamp timeStamp = new Timestamp（date.getTime（））; 
迭代器fileListIterator = fileList.iterator（）; 
 String zipFileURL =; 
 
 try {
 String ZIP_LOC = contextRootPath +WEB-INF+ SEP +TempZipFiles+ SEP; 
 BufferedInputStream origin = null; 
 zipFileURL = ZIP_LOC 
 +FITS。 + timeStamp.toString（）。replaceAll（：，。）。replaceAll（，。）+.zip; 
 FileOutputStream dest = new FileOutputStream（ZIP_LOC 
 +FITS。+ timeStamp.toString（）。replaceAll（：，。）。replaceAll（，。）+。压缩）; 
 ZipOutputStream out = new ZipOutputStream（new BufferedOutputStream（
 dest））; 
 
 // out.setMethod（ZipOutputStream.DEFLATED）; 
 byte data [] = new byte [BUFFER]; 
 
 while（fileListIterator.hasNext（））{
 
 String fileName =（String）fileListIterator.next（）; 
 System.out.println（Adding：+ fileName）; 
 FileInputStream fi = new FileInputStream（fileName）; 
 origin = new BufferedInputStream（fi，BUFFER）; 
 ZipEntry entry = new ZipEntry（fileName）; 
 out.putNextEntry（entry）; 
 int count; 
 while（（count = origin.read（data，0，BUFFER））！= -1）{
 out.write（data，0，count）; 
} 
 origin.close（）; 
} 
 
 out.close（）; 
} catch（Exception e）{
 e.printStackTrace（）; 
} 
 
返回zipFileURL; 
} 
  

解决方案

URL无法访问任何文件（直接）在WEB-INF下。我建议使用servlet将文件从任何保存的位置返回到

还建议将文件保存在您的webapp上下文之外

I have written a Java web application that allows a user to download files from a server. These files are quite large and so are zipped together before download.

It works like this:
1. The user gets a list of files that match his/her criteria
2. If the user likes a file and wants to download he/she selects it by checking a checkbox
3. The user then clicks "download"
4. The files are then zipped and stored on a servera
5. The user this then presented with a page which contains a link to the downloadable zip filea
6. However on downloading the zip file the file that is downloaded is 0 bytes in sizea

I have checked the remote server and the zip file is being created properly, all that is left is to serve the file the user somehow, can you see where I might be going wrong, or suggest a better way to serve the zip file.

The code that creates the link is:

<%   
String zipFileURL = (String) request.getAttribute("zipFileURL"); %>  
<p><a href="<% out.print(zipFileURL); %> ">Zip File Link</a></p>

The code that creates the zipFileURL variable is:

public static String zipFiles(ArrayList<String> fileList, String contextRootPath) {
        //time-stamping
          Date date = new Date();
        Timestamp timeStamp = new Timestamp(date.getTime());
    Iterator fileListIterator = fileList.iterator();
    String zipFileURL = "";

    try {
        String ZIP_LOC = contextRootPath + "WEB-INF" + SEP + "TempZipFiles" + SEP;
        BufferedInputStream origin = null;
        zipFileURL = ZIP_LOC
        + "FITS." + timeStamp.toString().replaceAll(":", ".").replaceAll(" ", ".") + ".zip";
        FileOutputStream dest = new FileOutputStream(ZIP_LOC
              + "FITS." + timeStamp.toString().replaceAll(":", ".").replaceAll(" ", ".") + ".zip");
        ZipOutputStream out = new ZipOutputStream(new BufferedOutputStream(
              dest));

        // out.setMethod(ZipOutputStream.DEFLATED);
        byte data[] = new byte[BUFFER];

        while(fileListIterator.hasNext()) { 

           String fileName = (String) fileListIterator.next();
           System.out.println("Adding: " + fileName);
           FileInputStream fi = new FileInputStream(fileName);
           origin = new BufferedInputStream(fi, BUFFER);
           ZipEntry entry = new ZipEntry(fileName);
           out.putNextEntry(entry);
           int count;
           while ((count = origin.read(data, 0, BUFFER)) != -1) {
              out.write(data, 0, count);
           }
           origin.close();            
       }

      out.close();
   } catch (Exception e) {
      e.printStackTrace();
   }

return zipFileURL;
    }

解决方案

A URL cannot access any files (directly) under WEB-INF. I'd suggest using a servlet to return the file from whatever location it was saved to

Would also suggest saving the file outside the context of your webapp

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