如何在不保存到磁盘的情况下将JarInputStream转换为JarFile？ [英] How can I convert a JarInputStream to a JarFile without saving to disk?

问题描述

我有一个Servlet，用户可以在其上传.jar文件以检查其 MANIFEST.MF 。

I've got a Servlet on which a user can upload a .jar file to check its MANIFEST.MF.

我知道以下内容可行：

JarInputStream in = new JarInputStream(new ByteArrayInputStream (fileItem.get()));
Manifest mf = in.getManifest(); 

不幸的是 getManifest（）方法解析关键：值和需要：（冒号+空格），简单的冒号是不够的。由于我正在使用的手机也可以工作，如果 MANIFEST.MF 只有冒号而不是冒号+空格，我想手动提取MANIFEST.MF，但我不想将文件保存在磁盘上。

Unfortunately the getManifest() method parses for Key: Value and needs the ": " (colon+space), a simple colon is not enough. Since the mobile phones I'm working with also work if the MANIFEST.MF only has colons and not colon+space, I'd like to extract the MANIFEST.MF manually, but I don't want to save the file on disk.

如果我有一个JarFile，我可以通过以下方式解析清单：

If I'd have a JarFile, I could parse the Manifest via:

JarFile jarFile = new JarFile(fileName);
InputStream in = jarFile.getInputStream(jarFile.getEntry("META-INF/MANIFEST.MF"));
BufferedReader br = new BufferedReader(new InputStreamReader(in));

String line;
while ((line = br.readLine()) != null) {
    String[] splitAr = line.split(":", 0);
    // ...

但不幸的是我不知道如何转换 JarInputStream （或 ByteArrayInputStream ）到 JarFile 。

But unfortunately I have no idea how I could convert a JarInputStream (or a ByteArrayInputStream) to a JarFile.

推荐答案

在这种情况下我会尝试做什么：

What I would try to do in this case:

• 使用 getNextEntry（）遍历jar中的所有条目 - 不是 getNextJarEntry（）！并且看看你是否可以通过这种方式到达清单


• 尝试使用 ZipInputStream 而不是更通用 - JarInputStream 实际上扩展了它 - 这应该让你有权获得 META-INF / MANIFEST.MF 文件。

• iterate through all the entries in the jar using getNextEntry() -- not getNextJarEntry()! and see if you can reach the manifest this way
• try to use a ZipInputStream instead which is more generic -- JarInputStream in fact extends it -- and that should give you access to get the META-INF/MANIFEST.MF file.

这篇关于如何在不保存到磁盘的情况下将JarInputStream转换为JarFile？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！