如何创建不会在父级中搜索加载类的ClassLoader [英] How do I create a ClassLoader that will not search the parent for loading classes

问题描述

我想我理解类加载层次结构是如何工作的。 （JVM首先查看父层次结构）

I think I understand how class-loading hierarchies work. (the JVM looks into the parent hierarchy first)

所以我想创建一个ClassLoader，或者使用现有的库，这是一个完全独立的范围，并且不会看一下父ClassLoading层次结构。实际上我正在寻找启动一个单独的JVM的相同效果，但没有真正这样做。

So I would like to create a ClassLoader, or use an existing library, that is a completely separate scope, and doesn't look at the parent ClassLoading hierarchy. Actually I'm looking for the same effect of launching a separate JVM, but without literally doing so.

我有信心这是可能的，但我很惊讶它很难找一个如何做到这一点的简单例子。

I'm confident this is possible, but surprised it was so hard to find a simple example of how to do that.

推荐答案

只需使用 URLClassLoader 并提供 null 作为父级。

Simply use the URLClassLoader and supply null as the parent.

File myDir = new File("/some/directory/");
ClassLoader loader = null;
try {
    URL url = myDir.toURL();         
    URL[] urls = new URL[]{url};
    loader = new URLClassLoader(urls, null);
} 
catch (MalformedURLException e) 
{
    // oops
}

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