包含罐子的罐子中的类的替换系统类加载器 [英] Replacement System Classloader for Classes In Jars containing Jars

问题描述

到目前为止，我看到的自定义类加载器示例涉及对 URLClassLoader 进行子类化，并使用该特定实例加载资源中的类.

So far, the examples I have seen for custom ClassLoaders involve subclassing the URLClassLoader, and using that specific instance to load classes in resources.

我曾尝试寻找替代方法来替换 SystemClassLoader，但徒劳无功，以便我的 ClassLoader 可以查询不在类路径中的类.

I have tried in vain to look for alternative methods to replace the SystemClassLoader, so that my ClassLoader can be consulted for classes not located in the classpath.

我尝试了 Thread.currentThread().setContextClassLoader，但它似乎不起作用.

I tried Thread.currentThread().setContextClassLoader, but it doesn't seem to work.

有可能吗?

推荐答案

虽然这是个老问题，但确实有办法替换系统 ClassLoader.但是，通过反思，您可能会得到比讨价还价更多的东西.

Though this is an old question, there is indeed a way to replace the system ClassLoader. You might get more than you bargained for, however, with reflection.

        Field scl = ClassLoader.class.getDeclaredField("scl"); // Get system class loader
        scl.setAccessible(true); // Set accessible
        scl.set(null, new YourClassLoader()); // Update it to your class loader

这应该适用于 Oracle JVM.

This should work on the Oracle JVM.

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