package com.smart.reflect;

public class Car {

    private String brand;

    private String color;

    private int maxSpeed;

    //默认构造函数

    public Car(){}

    //带参构造函数

    public Car(String brand, String color, int maxSpeed) {

        this.brand = brand;

        this.color = color;

        this.maxSpeed = maxSpeed;

    }

    //未带参方法

    public void introduce() {

        System.out.println("brand:" + brand + ";color:" + color + ";maxSpeed:" + maxSpeed);

    }

    public String getBrand() {

        return brand;

    }

    public void setBrand(String brand) {

        this.brand = brand;

    }

    public String getColor() {

        return color;

    }

    public void setColor(String color) {

        this.color = color;

    }

    public int getMaxSpeed() {

        return maxSpeed;

    }

    public void setMaxSpeed(int maxSpeed) {

        this.maxSpeed = maxSpeed;

    }

}

package com.smart.reflect;

import sun.reflect.CallerSensitive;

import java.lang.reflect.Constructor;

import java.lang.reflect.Method;

public class ReflectTest {

    public static Car initByDefaultConst() throws Throwable {

        /*

        类装载器工作机制：

         (1)装载：查找和导入Class文件

         (2)链接：

              1.校验：检查载入Class文件数据的正确性

              2.准备：给类的静态变量分配存储空间

              3.解析：将符号引用转化为直接引用（可选）

         (3)初始化：对类的静态变量、静态代码块执行初始化工作

        */

        // 1. 通过类加载器获取Car类对象

        ClassLoader loader = Thread.currentThread().getContextClassLoader();

        Class clazz = loader.loadClass("com.smart.reflect.Car");

        // 2. 获取类的默认构造器对象并通过它实例化Car

        Constructor constructor = clazz.getConstructor((Class[]) null);

        Car car = (Car) constructor.newInstance();

        // 3. 通过反射方法设置属性

        Method setBrand = clazz.getMethod("setBrand", String.class);

        setBrand.invoke(car, "红旗CA72");

        Method setColor = clazz.getMethod("setColor", String.class);

        setColor.invoke(car, "黑色");

        Method setMaxSpeed = clazz.getMethod("setMaxSpeed", int.class);

        setMaxSpeed.invoke(car, 200);

        return car;

    }

    public static void main(String[] args) throws Throwable {

        Car car = initByDefaultConst();

        car.introduce();

        //JVM装载类时使用“全盘负责委托机制”

        // 1.当一个ClassLoader装载一个类时，除非显式的使用另一个ClassLoader,该类所依赖及引用的类也由这个ClassLoader载入

        // 2.先委托父类装载器寻找目标类，只有在找不到的情况下才从自己的类路径中查找并装载目标类

    }

}