[Java基础]反射获取成员变量并使用

Posted 2021-08-15 Wecccccccc

代码如下:

package ClassObjectPack;

public class Student {
    private String name;
    int age;
    public String address;

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

    public Student() {
    }

    private Student(String name) {
        this.name = name;
    }

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

    private void function()
    {
        System.out.println("function");
    }

    public void method1()
    {
        System.out.println("method");
    }

    public void method2(String s)
    {
        System.out.println("method:"+s);
    }

    public String method3(String s,int i)
    {
        return s+","+i;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\\'' +
                ", age=" + age +
                ", address='" + address + '\\'' +
                '}';
    }
}

package ClassObjectPack01;

import java.lang.constant.DynamicCallSiteDesc;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;

public class ReflectDemo03 {
    public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException, InstantiationException, IllegalAccessException, NoSuchFieldException {
        Class<?> c = Class.forName("ClassObjectPack.Student");

//        Field getField(String name)
//        返回一个 Field对象，它反映此表示的类或接口的指定公共成员字段 类对象。
//        Field[] getFields()
//        返回包含一个数组 Field对象反射由此表示的类或接口的所有可访问的公共字段 类对象。

//        Field getDeclaredField(String name)
//        返回一个 Field对象，它反映此表示的类或接口的指定已声明字段 类对象。
//        Field[] getDeclaredFields()
//        返回的数组 Field对象反映此表示的类或接口声明的所有字段 类对象。


        Field[] fields = c.getFields();
        for (Field field:fields)
        {
            System.out.println(field);
        }


    System.out.println("-----------------------------------");

        Field[] fields01 = c.getDeclaredFields();
        for (Field field:fields01)
        {
            System.out.println(field);
        }

        System.out.println("--------------------------------------");

        Field addressField = c.getField("address");

      //获取无参构造方法创建对象
        Constructor<?> con = c.getConstructor();
        Object obj = con.newInstance();

        addressField.set(obj,"西安");

        System.out.println(obj);

    }
}

测试结果: