获取JAR文件的版本号 [英] Get a JAR File version number

问题描述

我有一个用于集群的应用程序，如果一个或多个失败，它将保持可用，我想实现一种方法来检查Java中jar文件的版本.

I have an application used in clustering to keep it available if one or more failed and I want to implement a way to check the version of the jar file in java.

我有这段代码可以做到这一点(例如:在MyClass类中):

I have this piece of code to do that (e.g.: in the class MyClass) :

        URLClassLoader cl = (URLClassLoader) (new MyClass ())
            .getClass().getClassLoader();
        URL url = cl.findResource("META-INF/MANIFEST.MF");
        Manifest manifest = new Manifest(url.openStream());
        attributes = manifest.getMainAttributes();
        String version = attributes.getValue("Implementation-Version");

当我将jar作为应用程序运行时，当我将jar文件用作其他应用程序中的librairie时，它可以很好地工作，但是我获得了另一个应用程序的版本号.

When i run the jar as an application it works fine BUT when i use the jar file as a librairie in an other application, i get the version number of the other application.

所以我的问题是，如何获取包含MyClass的jar的清单?

So my question is, how can i get the manifest of the jar where MyClass is contained ?

NB:我对使用静态约束的解决方案不感兴趣，例如 'classLoader.getRessource("MyJar.jar")'或File("MyJar.jar")

NB : I'm not interested in solution using static constraint like 'classLoader.getRessource("MyJar.jar")' or File("MyJar.jar")

推荐答案

最后，我从朋友那里得到了解决方案:

Finally i get the solution from a friend :

    // Get jarfile url
    String jarUrl = JarVersion.class
        .getProtectionDomain().getCodeSource()
        .getLocation().getFile();

    JarFile jar = new JarFile(new File(jarUrl));
    Manifest manifest = jar.getManifest();
    Attributes attributes = manifest.getMainAttributes();

    String version = attributes.getValue(IMPLEMENTATION_VERSION) 

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