1.首先写一基本的Java类User

package com.che.test;

public class User {

    private  String name;

}

2.写一应用类App

package com.che.test;

import java.lang.reflect.Array;

import java.lang.reflect.Field;

import java.lang.reflect.Method;

public class App {

   

    public static void main(String[] args) {

        String objName="com.che.test.User";

        try{

            Class cs=Class.forName(objName);

            Object obj=cs.newInstance();

            Field name=cs.getDeclaredField("name");

            name.setAccessible(true);

            System.out.println(name.get(obj));

            name.set(obj, "che");

            System.out.println(name.get(obj));

            name.setAccessible(false);

       }catch(Exception e){

            e.printStackTrace();

        }

    }

}