通过反射将一个类中字段的所有值复制到另一个类中 [英] Copy all values from fields in one class to another through reflection

问题描述

我有一个类，它基本上是另一个类的副本.

I have a class which is basically a copy of another class.

public class A {
  int a;
  String b;
}

public class CopyA {
  int a;
  String b;
}

我正在做的是在通过网络服务调用发送 CopyA 之前将 A 类的值放入 CopyA 中.现在我想创建一个反射方法，它基本上将所有相同的字段(按名称和类型)从 A 类复制到 CopyA 类.

What I am doing is putting values from class A into CopyA before sending CopyA through a webservice call. Now I would like to create a reflection-method that basically copies all fields that are identical (by name and type) from class A to class CopyA.

我该怎么做?

这是我到目前为止所拥有的，但它并不完全有效.我认为这里的问题是我试图在我循环的字段上设置一个字段.

This is what I have so far, but it doesn't quite work. I think the problem here is that I am trying to set a field on the field I am looping through.

private <T extends Object, Y extends Object> void copyFields(T from, Y too) {

    Class<? extends Object> fromClass = from.getClass();
    Field[] fromFields = fromClass.getDeclaredFields();

    Class<? extends Object> tooClass = too.getClass();
    Field[] tooFields = tooClass.getDeclaredFields();

    if (fromFields != null && tooFields != null) {
        for (Field tooF : tooFields) {
            logger.debug("toofield name #0 and type #1", tooF.getName(), tooF.getType().toString());
            try {
                // Check if that fields exists in the other method
                Field fromF = fromClass.getDeclaredField(tooF.getName());
                if (fromF.getType().equals(tooF.getType())) {
                    tooF.set(tooF, fromF);
                }
            } catch (SecurityException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (NoSuchFieldException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IllegalArgumentException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IllegalAccessException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
    }

我相信一定有人已经以某种方式这样做了

I am sure there must be someone that has already done this somehow

推荐答案

如果你不介意使用第三方库，BeanUtils 可以很容易地处理这个问题，使用 copyProperties(Object, Object).

If you don't mind using a third party library, BeanUtils from Apache Commons will handle this quite easily, using copyProperties(Object, Object).

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