import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
/**
 * 反射爆破案例，创建实例
 */
public class ReflectionBlast {
    public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, NoSuchMethodException, InvocationTargetException {
        // 获取User类的Class对象
        Class<?> userClass = Class.forName("reflection.User");
        // 通过public的无参构造器创建实例
        Object o = userClass.newInstance();
        System.out.println(o);  // User{age=21, name='dahe'}
        // 通过public的有参构造器创建实例
        Constructor<?> constructor = userClass.getConstructor(String.class);
        Object ww = constructor.newInstance("王伟");
        System.out.println(ww);  // User{age=21, name='王伟'}
        // 通过非public的有参构造器创建实例
        Constructor<?> declaredConstructor = userClass.getDeclaredConstructor(int.class, String.class);
        // 开启爆破模式
        declaredConstructor.setAccessible(true);
        Object ddd = declaredConstructor.newInstance(12, "ddd");
        System.out.println(ddd);  // User{age=12, name='ddd'}
    }
}
class User {
    private int age = 21;
    private String name = "dahe";
    public User() {
    }
    public User(String name) {
        this.name = name;
    }
    private User(int age, String name) {
        this.age = age;
        this.name = name;
    }
    @Override
    public String toString() {
        return "User{" +
                "age=" + age +
                ", name='" + name + '\'' +
                '}';
    }
}

import java.lang.reflect.Field;
/**
 * 反射爆破案例，爆破属性
 */
public class ReflectionBlastAttributes {
    public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, NoSuchFieldException {
        Class<?> stuClass = Class.forName("reflection.Student");
        // 创建一个对象
        Object o = stuClass.newInstance();
        Field age = stuClass.getField("age");
        // 操作公有属性
        age.set(o, 99);
        System.out.println(o);  // Student{age=99 name=null}
        // 操作私有静态属性
        Field name = stuClass.getDeclaredField("name");
        name.setAccessible(true);
        // 也可以写为name.set(null, "昆仑云");
        name.set(o, "昆仑云");
        System.out.println(o);  // Student{age=99 name=昆仑云}
        // 得到某一个属性
        System.out.println(age.get(o));  // 99
        System.out.println(name.get(null));  // 昆仑云
    }
}
class Student {
    public int age;
    private static String name;
    public Student() {
    }
    @Override
    public String toString() {
        return "Student{" +
                "age=" + age + "\tname=" + name +
                '}';
    }
}

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
/**
 * 反射爆破案例，爆破方法
 */
public class ReflectionBlastMethod {
    public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, NoSuchMethodException, InvocationTargetException {
        Class<?> bossClass = Class.forName("reflection.Boss");
        Object o = bossClass.newInstance();
        // 反射爆破公有方法
        Method hi = bossClass.getMethod("hi", String.class);
        hi.invoke(o, "dahedahe");  // dahedahe
        // 反射爆破私有静态方法
        Method say = bossClass.getDeclaredMethod("say", int.class, String.class, char.class);
        say.setAccessible(true);
        System.out.println(say.invoke(o, 12, "我的司机", 'a'));  // 12 我的司机 a
    }
}
class Boss {
    public int age;
    private static String name;
    public Boss() {
    }
    private static String say(int n, String s, char c) {
        return n + " " + s + " " + c;
    }
    public void hi(String s) {
        System.out.println(s);
    }
}