阅读我自己的 Jar 清单 [英] Reading my own Jar's Manifest

问题描述

我需要阅读 Manifest 文件，它提供了我的课程，但是当我使用:

I need to read the Manifest file, which delivered my class, but when I use:

getClass().getClassLoader().getResources(...)

我从加载到 Java 运行时的第一个 .jar 中获取了 MANIFEST.
我的应用程序将从小程序或 webstart 运行，
所以我想我将无法访问我自己的 .jar 文件.

I get the MANIFEST from the first .jar loaded into the Java Runtime.
My app will be running from an applet or a webstart,
so I will not have access to my own .jar file, I guess.

我实际上想从启动的 .jar 中读取 Export-package 属性Felix OSGi，所以我可以将这些包公开给 Felix.有什么想法吗?

I actually want to read the Export-package attribute from the .jar which started the Felix OSGi, so I can expose those packages to Felix. Any ideas?

推荐答案

您可以做以下两件事之一:

You can do one of two things:

1. 调用 getResources() 并遍历返回的 URL 集合，将它们作为清单读取，直到找到您的:

1. Call getResources() and iterate through the returned collection of URLs, reading them as manifests until you find yours:

Enumeration<URL> resources = getClass().getClassLoader()
  .getResources("META-INF/MANIFEST.MF");
while (resources.hasMoreElements()) {
    try {
      Manifest manifest = new Manifest(resources.nextElement().openStream());
      // check that this is your manifest and do what you need or get the next one
      ...
    } catch (IOException E) {
      // handle
    }
}

您可以尝试检查getClass().getClassLoader() 是否是java.net.URLClassLoader 的实例.大多数 Sun 类加载器都是，包括 AppletClassLoader.然后你可以投射它并调用已知的 findResource() - 至少对于小程序 - 直接返回所需的清单:

You can try checking whether getClass().getClassLoader() is an instance of java.net.URLClassLoader. Majority of Sun classloaders are, including AppletClassLoader. You can then cast it and call findResource() which has been known - for applets, at least - to return the needed manifest directly:

URLClassLoader cl = (URLClassLoader) getClass().getClassLoader();
try {
  URL url = cl.findResource("META-INF/MANIFEST.MF");
  Manifest manifest = new Manifest(url.openStream());
  // do stuff with it
  ...
} catch (IOException E) {
  // handle
}

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