Java ：（部分）类的序列化（不是对象！）

问题描述：

我目前正在执行一项任务，将一个组件及其依赖项打包在一起，并从中制作出一个包含所有需要的东西的独立组件。

I am currently working on a task to package a component and its dependencies together and makes a stand-alone component out of it that has all needed stuff included.

我遇到的情况是，我可能也需要在此组件中包含用户定义的类。

I have the situation that I might have user-defined classes which I need to include in this component, too.

我正在寻找一种以苗条/智能的方式序列化它们的方法。例如，这些类具有继承层次结构：

I am looking for a way to serialize them in a slim/smart way. These classes have a inheritance hierarchy for instance:

FrameWorkSuper
--------------
UserSuper 
UserClass

是否有一种只能序列化User的方法类的定义部分，以保持较小的占地面积？任何源自框架的内容都绝对包含在最终组件中。因此，我想序列化并稍后仅加载整个用户定义的部分，以使类获得框架部分也在包中。

Is there a way to serialize only the User-defined part of a class to keep the footprint small? Anything that originates from the framework is definitely in the final component included. Thus I want to serialize and load later only the user-defined part of the whole in a way that the class gets that the framework part is also in the package.

是

答

我认为您想做的是

如果没有这些类的字节码，而只有源代码，则传输用户定义的类的实际字节码。，您需要先对其进行编译。我建议使用 JavaCompiler 。
- 由于将所有内容编译到磁盘然后再次将其读取到字节数组有点繁琐，因此您可能要使用自己的FileManager和JavaFileObject实现，如有必要，我可以提供有关此步骤的详细信息。

创建一个自定义的类加载器，该加载器获取所有类的字节码，并将其findClass方法覆盖为类似

Create a custom classloader which gets the byte code of all the classes and override its findClass method to something like

// first try our cache of loaded classes
if (loadedClasses.containsKey(name)) {
    return loadedClasses.get(name);
}

// that didn't work, maybe the class was compiled but not yet loaded
if (compiledClasses.containsKey(name)) {
    // get the representation from the cache
    InMemoryClassJavaFileObject inMemoryRepresentation = compiledClasses.get(name);
    // let our parent define the class
    Class<?> clazz = defineClass(name, inMemoryRepresentation.getData(), 0, inMemoryRepresentation.getData().length);
    // and store it in the cache for later retrieval
    loadedClasses.put(name, clazz);
    return clazz;
}

请注意，您不需要创建 InMemoryClassJavaFileObject ，您可以简单地使用字节数组。

Note that you do not need to create InMemoryClassJavaFileObject, you can simply use a byte array.

这使您可以在远程站点*问类本身：您可以创建实例并使用其方法。

That gives you access to the class itself on the remote site: you can create instances and use their methods.

Java ：（部分）类的序列化（不是对象！）

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