如何实例化一个 ArrayList<?>并通过 Java 反射添加项目? [英] How to instantiate an ArrayList&lt;?&gt; and add an item through reflection with Java?

问题描述

我正在编写一个将 xml 转换为 Java 对象的反序列化方法.我想动态地执行此操作并避免编写对特定类型的硬编码引用.

I am writing a deserialization method that converts xml to a Java object. I would like to do this dynamically and avoid writing hard coded references to specific types.

例如，这是我的一个课程的简化版本.

For example this is a simplified version of one of my classes.

public class MyObject { 
   public ArrayList<SubObject> SubObjects = new ArrayList<SubObject>();
}

这是该方法的精简版:

public class Serializer {    
    public static <T> T fromXml(String xml, Class<T> c) {
       T obj = c.newInstance();       
       Field field = obj.getClass().getField("SubObjects");    
       //help : create instance of ArrayList<SubObject> and add an item
       //help#2 : field.set(obj, newArrayList);

       return obj;
    }
}

调用这个方法看起来像这样:

Calling this method would look like this:

MyObject obj = Serializer.fromXml("myxmldata", MyObject.class);

如果这是一个小问题，请原谅我，因为我是一名学习 Java 的 C# 开发人员.

Forgive me if this is a trivial problem as I am a C# developer learning Java.

谢谢！

推荐答案

应该非常接近:

Object list = field.getType().newInstance();

Method add = List.class.getDeclaredMethod("add",Object.class);

add.invoke(list, addToAddToList);

希望这会有所帮助.

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