在java中如何从对和对象的映射中获取值

Class<?> clazz = object.getClass();

Field field = clazz.getDeclaredField("fieldName");

field.setAccessible(true);

Object value = field.get(object);

import java.lang.reflect.Field;

public class Main {
    public static void main(String[] args) throws NoSuchFieldException, IllegalAccessException {
        // 创建一个对象
        Person person = new Person("John", 25);

        // 获取对象的Class对象
        Class<?> clazz = person.getClass();

        // 获取字段的Field对象
        Field nameField = clazz.getDeclaredField("name");
        Field ageField = clazz.getDeclaredField("age");

        // 设置字段可访问
        nameField.setAccessible(true);
        ageField.setAccessible(true);

        // 获取字段的值
        String name = (String) nameField.get(person);
        int age = (int) ageField.get(person);

        // 输出字段的值
        System.out.println("Name: " + name);
        System.out.println("Age: " + age);
    }
}

class Person {
    private String name;
    private int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }
}