[Java基础]反射获取成员变量并使用练习

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

public class ReflectDemo04 {
    public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException, InstantiationException, IllegalAccessException, NoSuchFieldException {
        Class<?> c = Class.forName("ClassObjectPack.Student");

        Constructor<?> con = c.getConstructor();
        Object obj = con.newInstance();

        System.out.println(obj);

        //getField只能拿公共的
//        Field nameFiled = c.getField("name");

        Field nameField = c.getDeclaredField("name");

        nameField.setAccessible(true);

        nameField.set(obj,"林青霞");

        System.out.println(obj);

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

        //s.age = 30

        Field ageField = c.getDeclaredField("age");
        ageField.setAccessible(true);

        ageField.set(obj,30);

        System.out.println(obj);

        Field addressField = c.getDeclaredField("address");
        addressField.setAccessible(true);//可有可无

        addressField.set(obj,"西安");

        System.out.println(obj);

    }

}

测试结果: