如何从Java反射中获取String字段的值？

Question

I have an object that has a String field. I can obtain this field by calling:

Field field = someObj.getClass().getField("strField");

I sett a Field#set(Object) method, for setting the value of this instance's field, but the respective getter seems to be Field#get(Object) , which is weird because I would have expected it to be Field#get() .

How do I obtain the value of the instance's strField ?

Answer 1

if you are using java.lang.reflect.Field , the "setter" is Field.set(Object,Object) and the "getter" is Field.get(Object) . in both cases, the first parameter is the instance on which you want to access the field.

Answer 2

Even without the getter or the setter methods for a property, you can change or get the value using an object reference and Java Reflection.

import java.lang.reflect.Field;

public class Bean {

    private String strField;

    public static void main(String[] args) throws Exception {
        Bean bean = new Bean();
        Field field = bean.getClass().getDeclaredField("strField");
        field.set(bean, "Hello");
        System.out.println(field.get(bean));
    }

}

Answer 3

Easiest way is to use BeanUtils :

String s = BeanUtils.getProperty(someObj, "strField");

Note that BeanUtils will attempt to convert your property into string. You need to have a getter and setter of the property