通过反射创建运行时类的对象

person类如下：

public class Person {
    private String name;
    public int age;

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

    }
    private Person(String name){
        this.name = name;
    }
    public Person(){
        System.out.println("Person()");

    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
    public void show(){
        System.out.println("输出下一条语句，你会获得金币");
    }
    private String showNext(String next){
        System.out.println("再试一试，你可以获得"+next+"枚金币");
        return next;

    }
}

public class testNewInstance {
    //通过反射创建对应类的对象
    public static void main(String[] args) {
        try {
            test1();
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
    public static void test1() throws InstantiationException, IllegalAccessException {
        Class clazz = Person.class;//此处的Person取决于你想调用的类名
        // newInstance():调用此方法，创建对应的运行时类的对象
        //内部调用了运行时的空参构造器
        Person obj =(Person) clazz.newInstance();
        System.out.println(obj);
        //此调用方法想要实现必须运行时类必须提供空参构造器，访问权限通常设置为public
    }
}

public class testReflection {
    public static void main(String[] args) {
        try {
            test1();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public static void test1() throws NoSuchMethodException, InvocationTargetException, InstantiationException, IllegalAccessException, NoSuchFieldException {
        Class clazz = Person.class;
        //通过反射来创建Person类的对象
        //括号中填写类中含有的参数类型
        Constructor cons = clazz.getConstructor(String.class,int.class);
        Object obj= cons.newInstance("张三",12);
        Person p = (Person) obj;
        System.out.println(p.toString());

        //2：通过反射，调用对象的指定的属性和方法
        Field age= clazz.getDeclaredField("age");
        age.set(p,10);
        System.out.println(p.toString());

        //调用方法,通过invoke
        Method show = clazz.getDeclaredMethod("show");
        show.invoke(p);
        System.out.println("***************************");

        //普通的调用不能调用私有结构，但是通过反射是可以调用person的私有结构的
        //调用私有的构造器
        Constructor cons1= clazz.getDeclaredConstructor(String.class);
        cons1.setAccessible(true);
        Person p1 = (Person) cons1.newInstance("Jerry");
        System.out.println(p1);

        //调用私有的属性
        Field name= clazz.getDeclaredField("name");
        name.setAccessible(true);
        name.set(p1,"并夕夕");
        System.out.println(p1);

        //调用私有的方法
        Method method= clazz.getDeclaredMethod("showNext", String.class);
        method.setAccessible(true);
        //返回值为传入方法的值
        String next=(String) method.invoke(p1,"九");
        System.out.println(next);




    }

}