本文介绍了用反射设置私有字段值的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有2个班级:Father和Child
public class Father implements Serializable, JSONInterface { private String a_field; //setter and getter here } public class Child extends Father { //empty class }通过反射,我想在Child类中设置a_field:
With reflection I want to set a_field in Child class:
Class<?> clazz = Class.forName("Child"); Object cc = clazz.newInstance(); Field f1 = cc.getClass().getField("a_field"); f1.set(cc, "reflecting on life"); String str1 = (String) f1.get(cc.getClass()); System.out.println("field: " + str1);但我有一个例外:
线程"main"中的异常java.lang.NoSuchFieldException:a_field
Exception in thread "main" java.lang.NoSuchFieldException: a_field
但是,如果我尝试:
Child child = new Child(); child.setA_field("123");有效.
使用setter方法,我有同样的问题:
Using setter method I have same problem:
method = cc.getClass().getMethod("setA_field"); method.invoke(cc, new Object[] { "aaaaaaaaaaaaaa" });推荐答案
要访问私有字段,您需要将Field::setAccessible设置为true.您可以离开超类领域.这段代码有效:
To access a private field you need to set Field::setAccessible to true. You can pull the field off the super class. This code works:
Class<?> clazz = Child.class; Object cc = clazz.newInstance(); Field f1 = cc.getClass().getSuperclass().getDeclaredField("a_field"); f1.setAccessible(true); f1.set(cc, "reflecting on life"); String str1 = (String) f1.get(cc); System.out.println("field: " + str1);更多推荐
用反射设置私有字段值
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