我可以使用反射在类中添加新字段吗 [英] Can I add new fields in a Class using reflection

问题描述

如果我有类文字对象，我可以向类添加新字段吗?我如何确定在该类文字中引用或使用了特定类?

Can I add a new field to a class if I have its class literal object and how can I determine that a particular Class is referenced or used in that class literal ?

推荐答案

您不能直接向 Class 对象添加新字段.您可以使用第三方 API 来生成或修改类(例如 ASM、BCEL)，但最好避免使用它们，因为它们会增加很多复杂性.

You can't directly add a new field to the Class object. There are third-party APIs that you can use to do class generation or modification (e.g. ASM, BCEL), though they're best avoided because they add a lot of complexity.

至于问题的第二部分，您可以使用 Class 对象来浏览字段并检查它们.

As for the second part of your question, you can use the Class object to go through the fields and examine them.

// NOTE : this only looks at the fields in A and not it's superclass.
//        you'll have to do a recursive lookup if you want super's fields too.
for(Field field : A.class.getDeclaredFields()) {
    if(B.class.equals(field.getType()) {
        System.out.println("A." + field.getName() + " is of type B");
    }
}

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