如何使用动态创建的字段？

var obj = {};
var fieldName = "dynamicField";
var fieldValue = "dynamicValue";

obj[fieldName] = fieldValue;

console.log(obj.dynamicField); // 输出 "dynamicValue"

import java.lang.reflect.Field;

public class DynamicFieldExample {
    public static void main(String[] args) throws NoSuchFieldException, IllegalAccessException {
        Object obj = new Object();
        String fieldName = "dynamicField";
        String fieldValue = "dynamicValue";

        Field field = obj.getClass().getDeclaredField(fieldName);
        field.setAccessible(true);
        field.set(obj, fieldValue);

        System.out.println(field.get(obj)); // 输出 "dynamicValue"
    }
}